Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova...

145
Problem solving by search Tom´ s Svoboda Vision for Robots and Autonomous Systems, Center for Machine Perception Department of Cybernetics, Faculty of Electrical Engineering, Czech Technical University in Prague February 27, 2019 1 / 33

Transcript of Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova...

Page 1: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Problem solving by search

Tomas Svoboda

Vision for Robots and Autonomous Systems, Center for Machine PerceptionDepartment of Cybernetics,

Faculty of Electrical Engineering, Czech Technical University in Prague

February 27, 2019

1 / 33

Page 2: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Outline

I Search problem.

I State space graphs.

I Search trees.

I Strategies, which tree branches to choose?

I Strategy/Algorithm properties?

I Programming instrastructure

2 / 33

Page 3: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Example: Romania

Giurgiu

UrziceniHirsova

Eforie

Neamt

Oradea

Zerind

Arad

Timisoara

Lugoj

Mehadia

DobretaCraiova

Sibiu Fagaras

Pitesti

Vaslui

Iasi

Rimnicu Vilcea

Bucharest

71

75

118

111

70

75

120

151

140

99

80

97

101

211

138

146 85

90

98

142

92

87

86

3 / 33

Ok, start with a simple one, almost everybody knows about the navigation- path planning problem. Waze, Garmin, . . .

Can you think about more problems?

Page 4: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Example: Romania

Goal:be in Bucharest

Problem formulation:states: position in a city (cities)actions: drive between cities

Solution:Sequence of cities (path)

Giurgiu

UrziceniHirsova

Eforie

Neamt

Oradea

Zerind

Arad

Timisoara

Lugoj

Mehadia

DobretaCraiova

Sibiu Fagaras

Pitesti

Vaslui

Iasi

Rimnicu Vilcea

Bucharest

71

75

118

111

70

75

120

151

140

99

80

97

101

211

138

146 85

90

98

142

92

87

86

4 / 33

Classical problem from the Book [1], we use it, too.

Page 5: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Example: Romania

Goal:be in Bucharest

Problem formulation:states: position in a city (cities)actions: drive between cities

Solution:Sequence of cities (path)

Giurgiu

UrziceniHirsova

Eforie

Neamt

Oradea

Zerind

Arad

Timisoara

Lugoj

Mehadia

DobretaCraiova

Sibiu Fagaras

Pitesti

Vaslui

Iasi

Rimnicu Vilcea

Bucharest

71

75

118

111

70

75

120

151

140

99

80

97

101

211

138

146 85

90

98

142

92

87

86

4 / 33

Classical problem from the Book [1], we use it, too.

Page 6: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Example: Romania

Goal:be in Bucharest

Problem formulation:states: position in a city (cities)actions: drive between cities

Solution:Sequence of cities (path)

Giurgiu

UrziceniHirsova

Eforie

Neamt

Oradea

Zerind

Arad

Timisoara

Lugoj

Mehadia

DobretaCraiova

Sibiu Fagaras

Pitesti

Vaslui

Iasi

Rimnicu Vilcea

Bucharest

71

75

118

111

70

75

120

151

140

99

80

97

101

211

138

146 85

90

98

142

92

87

86

4 / 33

Classical problem from the Book [1], we use it, too.

Page 7: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Example: Romania

Goal:be in Bucharest

Problem formulation:states: position in a city (cities)actions: drive between cities

Solution:Sequence of cities (path)

Giurgiu

UrziceniHirsova

Eforie

Neamt

Oradea

Zerind

Arad

Timisoara

Lugoj

Mehadia

DobretaCraiova

Sibiu Fagaras

Pitesti

Vaslui

Iasi

Rimnicu Vilcea

Bucharest

71

75

118

111

70

75

120

151

140

99

80

97

101

211

138

146 85

90

98

142

92

87

86

4 / 33

Classical problem from the Book [1], we use it, too.

Page 8: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Example: Romania

Goal:be in Bucharest

Problem formulation:states: position in a city (cities)actions: drive between cities

Solution:Sequence of cities (path)

Giurgiu

UrziceniHirsova

Eforie

Neamt

Oradea

Zerind

Arad

Timisoara

Lugoj

Mehadia

DobretaCraiova

Sibiu Fagaras

Pitesti

Vaslui

Iasi

Rimnicu Vilcea

Bucharest

71

75

118

111

70

75

120

151

140

99

80

97

101

211

138

146 85

90

98

142

92

87

86

4 / 33

Classical problem from the Book [1], we use it, too.

Page 9: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Example: The 8-puzzle

2

Start State Goal State

51 3

4 6

7 8

5

1

2

3

4

6

7

8

5

states?actions?solution?cost?

5 / 33

Also known as n − 1 puzzle.

Page 10: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Example: Vacuum cleaner

R

L

S S

S S

R

L

R

L

R

L

S

SS

S

L

L

LL R

R

R

R

states?actions?solution?cost?

6 / 33

Page 11: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

A Search Problem

I State space (including Start/Initial state): position, boardconfiguration,

I Actions : drive to, Up, Down, Left . . .

I Transition model : Given state and action return state (and cost)

I Goal test : Are we done?

7 / 33

We will use the terminology throught the next 5-6 lectures; also for Markov

(Sequential) Decision Processes, Reinforcement Learning

Page 12: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

A Search Problem

I State space (including Start/Initial state): position, boardconfiguration,

I Actions : drive to, Up, Down, Left . . .

I Transition model : Given state and action return state (and cost)

I Goal test : Are we done?

7 / 33

We will use the terminology throught the next 5-6 lectures; also for Markov

(Sequential) Decision Processes, Reinforcement Learning

Page 13: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

A Search Problem

I State space (including Start/Initial state): position, boardconfiguration,

I Actions : drive to, Up, Down, Left . . .

I Transition model : Given state and action return state (and cost)

I Goal test : Are we done?

7 / 33

We will use the terminology throught the next 5-6 lectures; also for Markov

(Sequential) Decision Processes, Reinforcement Learning

Page 14: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

A Search Problem

I State space (including Start/Initial state): position, boardconfiguration,

I Actions : drive to, Up, Down, Left . . .

I Transition model : Given state and action return state (and cost)

I Goal test : Are we done?

7 / 33

We will use the terminology throught the next 5-6 lectures; also for Markov

(Sequential) Decision Processes, Reinforcement Learning

Page 15: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

State Space Graphs

State space graph: a representation of asearch problem

I Graph Nodes – states – are abstractedworld configurations

I Arcs represent action results

I Goal test – a set of goal nodes

Each state occurs only once in a state (search)space.

S b

c

d

G

a

8 / 33

Formalizing a real world problem – (creating) state space graph – could be

a problem of itself. I put creating into brackets is it may be also infinite.

Page 16: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Search Trees

Possible futures

Here we startS

a b c

I A “what if” tree of plans and their outcomes

I Start node is the root

I Children are successors

I Nodes show/contains states, but correspond to plans that achievethose states

9 / 33

• What if decision about an action, repeats . . .

• Nodes in the search tree are not the same as the nodes in the statespace graph.

Page 17: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

State Space Graphs vs. Search Trees

S b

c

d

G

a

S

a

S

a b c

b

a

S

d

S G

c

G a b

How big is the search tree?

10 / 33

• There could be multiple search trees, depending ot the algorithm.

• A search tree can be much bigger than the state space.

• Both items will be discussed next.

Page 18: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

State Space Graphs vs. Search Trees

S b

c

d

G

a

S

a

S

a b c

b

a

S

d

S G

c

G a b

How big is the search tree?

10 / 33

• There could be multiple search trees, depending ot the algorithm.

• A search tree can be much bigger than the state space.

• Both items will be discussed next.

Page 19: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

State Space Graphs vs. Search Trees

S b

c

d

G

a

S

a

S

a b c

b

a

S

d

S G

c

G a b

How big is the search tree?

10 / 33

• There could be multiple search trees, depending ot the algorithm.

• A search tree can be much bigger than the state space.

• Both items will be discussed next.

Page 20: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

State Space Graphs vs. Search Trees

S b

c

d

G

a

S

a

S

a b c

b

a

S

d

S G

c

G a b

How big is the search tree?

10 / 33

• There could be multiple search trees, depending ot the algorithm.

• A search tree can be much bigger than the state space.

• Both items will be discussed next.

Page 21: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

State Space Graphs vs. Search Trees

S b

c

d

G

a

S

a

S

a b c

b

a

S

d

S G

c

G a b

How big is the search tree?

10 / 33

• There could be multiple search trees, depending ot the algorithm.

• A search tree can be much bigger than the state space.

• Both items will be discussed next.

Page 22: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

State Space Graphs vs. Search Trees

S b

c

d

G

a

S

a

S

a b c

b

a

S

d

S G

c

G a b

How big is the search tree?

10 / 33

• There could be multiple search trees, depending ot the algorithm.

• A search tree can be much bigger than the state space.

• Both items will be discussed next.

Page 23: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

State Space Graphs vs. Search Trees

S b

c

d

G

a

S

a

S

a b c

b

a

S

d

S G

c

G a b

How big is the search tree?

10 / 33

• There could be multiple search trees, depending ot the algorithm.

• A search tree can be much bigger than the state space.

• Both items will be discussed next.

Page 24: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

State Space Graphs vs. Search Trees

S b

c

d

G

a

S

a

S

a b c

b

a

S

d

S G

c

G a b

How big is the search tree?

10 / 33

• There could be multiple search trees, depending ot the algorithm.

• A search tree can be much bigger than the state space.

• Both items will be discussed next.

Page 25: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

State Space Graphs vs. Search Trees

S b

c

d

G

a

S

a

S

a b c

b

a

S

d

S G

c

G a b

How big is the search tree?

10 / 33

• There could be multiple search trees, depending ot the algorithm.

• A search tree can be much bigger than the state space.

• Both items will be discussed next.

Page 26: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

State Space Graphs vs. Search Trees

S b

c

d

G

a

S

a

S

a b c

b

a

S

d

S G

c

G a b

How big is the search tree?

10 / 33

• There could be multiple search trees, depending ot the algorithm.

• A search tree can be much bigger than the state space.

• Both items will be discussed next.

Page 27: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

State Space Graphs vs. Search Trees

S b

c

d

G

a

S

a

S

a b c

b

a

S

d

S G

c

G a b

How big is the search tree?

10 / 33

• There could be multiple search trees, depending ot the algorithm.

• A search tree can be much bigger than the state space.

• Both items will be discussed next.

Page 28: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

State Space Graphs vs. Search Trees

S b

c

d

G

a

S

a

S

a b c

b

a

S

d

S G

c

G a b

How big is the search tree?

10 / 33

• There could be multiple search trees, depending ot the algorithm.

• A search tree can be much bigger than the state space.

• Both items will be discussed next.

Page 29: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

State Space Graphs vs. Search Trees

S b

c

d

G

a

S

a

S

a b c

b

a

S

d

S G

c

G a b

How big is the search tree?

10 / 33

• There could be multiple search trees, depending ot the algorithm.

• A search tree can be much bigger than the state space.

• Both items will be discussed next.

Page 30: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

State Space Graphs vs. Search Trees

S b

c

d

G

a

S

a

S

a b c

b

a

S

d

S G

c

G a b

How big is the search tree?

10 / 33

• There could be multiple search trees, depending ot the algorithm.

• A search tree can be much bigger than the state space.

• Both items will be discussed next.

Page 31: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Search tree for Romania(a) The initial state

(b) After expanding Arad

(c) After expanding Sibiu

Rimnicu Vilcea LugojArad Fagaras Oradea AradArad Oradea

Rimnicu Vilcea Lugoj

ZerindSibiu

Arad Fagaras Oradea

Timisoara

AradArad Oradea

Lugoj AradArad Oradea

Zerind

Arad

Sibiu Timisoara

Arad

Rimnicu Vilcea

Zerind

Arad

Sibiu

Arad Fagaras Oradea

Timisoara

11 / 33

Page 32: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Search elements

(a) The initial state

(b) After expanding Arad

(c) After expanding Sibiu

Rimnicu Vilcea LugojArad Fagaras Oradea AradArad Oradea

Rimnicu Vilcea Lugoj

ZerindSibiu

Arad Fagaras Oradea

Timisoara

AradArad Oradea

Lugoj AradArad Oradea

Zerind

Arad

Sibiu Timisoara

Arad

Rimnicu Vilcea

Zerind

Arad

Sibiu

Arad Fagaras Oradea

Timisoara

I Expand plans - possible ways (tree nodes).

I Manage/Maintain fringe (or frontier ) of plans underconsideration.

I Expand new nodes wisely(?).

12 / 33

Page 33: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Tree search algorithm

(a) The initial state

(b) After expanding Arad

(c) After expanding Sibiu

Rimnicu Vilcea LugojArad Fagaras Oradea AradArad Oradea

Rimnicu Vilcea Lugoj

ZerindSibiu

Arad Fagaras Oradea

Timisoara

AradArad Oradea

Lugoj AradArad Oradea

Zerind

Arad

Sibiu Timisoara

Arad

Rimnicu Vilcea

Zerind

Arad

Sibiu

Arad Fagaras Oradea

Timisoara

function tree search(problem) return a solution or failureinitialize by using the initial state of the problemloop

if no candidates for expansion then return failureelse choose a leaf node for expansionend ifif the node contains a goal state then return the solutionend ifExpand the node and add the resulting nodes to the tree

end loopend function

13 / 33

Page 34: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Tree search algorithm

(a) The initial state

(b) After expanding Arad

(c) After expanding Sibiu

Rimnicu Vilcea LugojArad Fagaras Oradea AradArad Oradea

Rimnicu Vilcea Lugoj

ZerindSibiu

Arad Fagaras Oradea

Timisoara

AradArad Oradea

Lugoj AradArad Oradea

Zerind

Arad

Sibiu Timisoara

Arad

Rimnicu Vilcea

Zerind

Arad

Sibiu

Arad Fagaras Oradea

Timisoara

function tree search(problem) return a solution or failureinitialize by using the initial state of the problemloop

if no candidates for expansion then return failureelse choose a leaf node for expansionend ifif the node contains a goal state then return the solutionend ifExpand the node and add the resulting nodes to the tree

end loopend function

13 / 33

Page 35: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Tree search algorithm

(a) The initial state

(b) After expanding Arad

(c) After expanding Sibiu

Rimnicu Vilcea LugojArad Fagaras Oradea AradArad Oradea

Rimnicu Vilcea Lugoj

ZerindSibiu

Arad Fagaras Oradea

Timisoara

AradArad Oradea

Lugoj AradArad Oradea

Zerind

Arad

Sibiu Timisoara

Arad

Rimnicu Vilcea

Zerind

Arad

Sibiu

Arad Fagaras Oradea

Timisoara

function tree search(problem) return a solution or failureinitialize by using the initial state of the problemloop

if no candidates for expansion then return failureelse choose a leaf node for expansionend ifif the node contains a goal state then return the solutionend ifExpand the node and add the resulting nodes to the tree

end loopend function

13 / 33

Page 36: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Tree search algorithm

(a) The initial state

(b) After expanding Arad

(c) After expanding Sibiu

Rimnicu Vilcea LugojArad Fagaras Oradea AradArad Oradea

Rimnicu Vilcea Lugoj

ZerindSibiu

Arad Fagaras Oradea

Timisoara

AradArad Oradea

Lugoj AradArad Oradea

Zerind

Arad

Sibiu Timisoara

Arad

Rimnicu Vilcea

Zerind

Arad

Sibiu

Arad Fagaras Oradea

Timisoara

function tree search(problem) return a solution or failureinitialize by using the initial state of the problemloop

if no candidates for expansion then return failureelse choose a leaf node for expansionend ifif the node contains a goal state then return the solutionend ifExpand the node and add the resulting nodes to the tree

end loopend function

13 / 33

Page 37: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Tree search algorithm

(a) The initial state

(b) After expanding Arad

(c) After expanding Sibiu

Rimnicu Vilcea LugojArad Fagaras Oradea AradArad Oradea

Rimnicu Vilcea Lugoj

ZerindSibiu

Arad Fagaras Oradea

Timisoara

AradArad Oradea

Lugoj AradArad Oradea

Zerind

Arad

Sibiu Timisoara

Arad

Rimnicu Vilcea

Zerind

Arad

Sibiu

Arad Fagaras Oradea

Timisoara

function tree search(problem) return a solution or failureinitialize by using the initial state of the problemloop

if no candidates for expansion then return failureelse choose a leaf node for expansionend ifif the node contains a goal state then return the solutionend ifExpand the node and add the resulting nodes to the tree

end loopend function

13 / 33

Page 38: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Tree search algorithm

(a) The initial state

(b) After expanding Arad

(c) After expanding Sibiu

Rimnicu Vilcea LugojArad Fagaras Oradea AradArad Oradea

Rimnicu Vilcea Lugoj

ZerindSibiu

Arad Fagaras Oradea

Timisoara

AradArad Oradea

Lugoj AradArad Oradea

Zerind

Arad

Sibiu Timisoara

Arad

Rimnicu Vilcea

Zerind

Arad

Sibiu

Arad Fagaras Oradea

Timisoara

function tree search(problem) return a solution or failureinitialize by using the initial state of the problemloop

if no candidates for expansion then return failureelse choose a leaf node for expansionend ifif the node contains a goal state then return the solutionend ifExpand the node and add the resulting nodes to the tree

end loopend function

13 / 33

Page 39: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Tree search algorithm

(a) The initial state

(b) After expanding Arad

(c) After expanding Sibiu

Rimnicu Vilcea LugojArad Fagaras Oradea AradArad Oradea

Rimnicu Vilcea Lugoj

ZerindSibiu

Arad Fagaras Oradea

Timisoara

AradArad Oradea

Lugoj AradArad Oradea

Zerind

Arad

Sibiu Timisoara

Arad

Rimnicu Vilcea

Zerind

Arad

Sibiu

Arad Fagaras Oradea

Timisoara

function tree search(problem) return a solution or failureinitialize by using the initial state of the problemloop

if no candidates for expansion then return failureelse choose a leaf node for expansionend ifif the node contains a goal state then return the solutionend ifExpand the node and add the resulting nodes to the tree

end loopend function

13 / 33

Page 40: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Example of a tree search

a

S

b

c

d

e

f

G

S

a

b

e f

G

c d

Which nodes to explore?What are the properties of a strategy/algorithm?

14 / 33

Before going to the next slide, think about algorithms. What properties of

an algorithm would you want?

Page 41: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Example of a tree search

a

S

b

c

d

e

f

G

S

a

b

e f

G

c d

Which nodes to explore?What are the properties of a strategy/algorithm?

14 / 33

Before going to the next slide, think about algorithms. What properties of

an algorithm would you want?

Page 42: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Example of a tree search

a

S

b

c

d

e

f

G

S

a

b

e f

G

c d

Which nodes to explore?What are the properties of a strategy/algorithm?

14 / 33

Before going to the next slide, think about algorithms. What properties of

an algorithm would you want?

Page 43: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Example of a tree search

a

S

b

c

d

e

f

G

S

a

b

e f

G

c d

Which nodes to explore?What are the properties of a strategy/algorithm?

14 / 33

Before going to the next slide, think about algorithms. What properties of

an algorithm would you want?

Page 44: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Example of a tree search

a

S

b

c

d

e

f

G

S

a

b

e f

G

c d

Which nodes to explore?What are the properties of a strategy/algorithm?

14 / 33

Before going to the next slide, think about algorithms. What properties of

an algorithm would you want?

Page 45: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Example of a tree search

a

S

b

c

d

e

f

G

S

a

b

e f

G

c d

Which nodes to explore?What are the properties of a strategy/algorithm?

14 / 33

Before going to the next slide, think about algorithms. What properties of

an algorithm would you want?

Page 46: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Example of a tree search

a

S

b

c

d

e

f

G

S

a

b

e f

G

c d

Which nodes to explore?What are the properties of a strategy/algorithm?

14 / 33

Before going to the next slide, think about algorithms. What properties of

an algorithm would you want?

Page 47: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Example of a tree search

a

S

b

c

d

e

f

G

S

a

b

e f

G

c d

Which nodes to explore?What are the properties of a strategy/algorithm?

14 / 33

Before going to the next slide, think about algorithms. What properties of

an algorithm would you want?

Page 48: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Example of a tree search

a

S

b

c

d

e

f

G

S

a

b

e f

G

c d

Which nodes to explore?What are the properties of a strategy/algorithm?

14 / 33

Before going to the next slide, think about algorithms. What properties of

an algorithm would you want?

Page 49: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Example of a tree search

a

S

b

c

d

e

f

G

S

a

b

e f

G

c d

Which nodes to explore?What are the properties of a strategy/algorithm?

14 / 33

Before going to the next slide, think about algorithms. What properties of

an algorithm would you want?

Page 50: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Search (algorithm) properties

I Guaranteed to find a solution (if exists)? Complete?

I Guaranteed to find the least cost path? Optimal?

I How many steps - an operation with a node? Time complexity?

I How many nodes to remember? Space/Memory complexity?

How many nodes in a tree? What are tree parameters?

15 / 33

Draw a (symbolic–think about a triangle) sketch of a (search) tree. It maygrow upwards or downwards. How would you characterize/parametrize sizeof a tree.

• Depth of the tree d .

• Max-Depth of the treem. Can be ∞.

• Branching factor b.

• s denotes theshallowest Goal.

• How many nodes inthe whole tree?

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 51: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Search (algorithm) properties

I Guaranteed to find a solution (if exists)? Complete?

I Guaranteed to find the least cost path? Optimal?

I How many steps - an operation with a node? Time complexity?

I How many nodes to remember? Space/Memory complexity?

How many nodes in a tree? What are tree parameters?

15 / 33

Draw a (symbolic–think about a triangle) sketch of a (search) tree. It maygrow upwards or downwards. How would you characterize/parametrize sizeof a tree.

• Depth of the tree d .

• Max-Depth of the treem. Can be ∞.

• Branching factor b.

• s denotes theshallowest Goal.

• How many nodes inthe whole tree?

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 52: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Search (algorithm) properties

I Guaranteed to find a solution (if exists)? Complete?

I Guaranteed to find the least cost path? Optimal?

I How many steps - an operation with a node? Time complexity?

I How many nodes to remember? Space/Memory complexity?

How many nodes in a tree? What are tree parameters?

15 / 33

Draw a (symbolic–think about a triangle) sketch of a (search) tree. It maygrow upwards or downwards. How would you characterize/parametrize sizeof a tree.

• Depth of the tree d .

• Max-Depth of the treem. Can be ∞.

• Branching factor b.

• s denotes theshallowest Goal.

• How many nodes inthe whole tree?

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 53: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Search (algorithm) properties

I Guaranteed to find a solution (if exists)? Complete?

I Guaranteed to find the least cost path? Optimal?

I How many steps - an operation with a node? Time complexity?

I How many nodes to remember? Space/Memory complexity?

How many nodes in a tree? What are tree parameters?

15 / 33

Draw a (symbolic–think about a triangle) sketch of a (search) tree. It maygrow upwards or downwards. How would you characterize/parametrize sizeof a tree.

• Depth of the tree d .

• Max-Depth of the treem. Can be ∞.

• Branching factor b.

• s denotes theshallowest Goal.

• How many nodes inthe whole tree?

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 54: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Search (algorithm) properties

I Guaranteed to find a solution (if exists)? Complete?

I Guaranteed to find the least cost path? Optimal?

I How many steps - an operation with a node? Time complexity?

I How many nodes to remember? Space/Memory complexity?

How many nodes in a tree? What are tree parameters?

15 / 33

Draw a (symbolic–think about a triangle) sketch of a (search) tree. It maygrow upwards or downwards. How would you characterize/parametrize sizeof a tree.

• Depth of the tree d .

• Max-Depth of the treem. Can be ∞.

• Branching factor b.

• s denotes theshallowest Goal.

• How many nodes inthe whole tree?

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 55: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Search (algorithm) properties

I Guaranteed to find a solution (if exists)? Complete?

I Guaranteed to find the least cost path? Optimal?

I How many steps - an operation with a node? Time complexity?

I How many nodes to remember? Space/Memory complexity?

How many nodes in a tree? What are tree parameters?

15 / 33

Draw a (symbolic–think about a triangle) sketch of a (search) tree. It maygrow upwards or downwards. How would you characterize/parametrize sizeof a tree.

• Depth of the tree d .

• Max-Depth of the treem. Can be ∞.

• Branching factor b.

• s denotes theshallowest Goal.

• How many nodes inthe whole tree?

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 56: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Search (algorithm) properties

I Guaranteed to find a solution (if exists)? Complete?

I Guaranteed to find the least cost path? Optimal?

I How many steps - an operation with a node? Time complexity?

I How many nodes to remember? Space/Memory complexity?

How many nodes in a tree? What are tree parameters?

15 / 33

Draw a (symbolic–think about a triangle) sketch of a (search) tree. It maygrow upwards or downwards. How would you characterize/parametrize sizeof a tree.

• Depth of the tree d .

• Max-Depth of the treem. Can be ∞.

• Branching factor b.

• s denotes theshallowest Goal.

• How many nodes inthe whole tree?

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 57: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Search (algorithm) properties

I Guaranteed to find a solution (if exists)? Complete?

I Guaranteed to find the least cost path? Optimal?

I How many steps - an operation with a node? Time complexity?

I How many nodes to remember? Space/Memory complexity?

How many nodes in a tree? What are tree parameters?

15 / 33

Draw a (symbolic–think about a triangle) sketch of a (search) tree. It maygrow upwards or downwards. How would you characterize/parametrize sizeof a tree.

• Depth of the tree d .

• Max-Depth of the treem. Can be ∞.

• Branching factor b.

• s denotes theshallowest Goal.

• How many nodes inthe whole tree?

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 58: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Search (algorithm) properties

I Guaranteed to find a solution (if exists)? Complete?

I Guaranteed to find the least cost path? Optimal?

I How many steps - an operation with a node? Time complexity?

I How many nodes to remember? Space/Memory complexity?

How many nodes in a tree? What are tree parameters?

15 / 33

Draw a (symbolic–think about a triangle) sketch of a (search) tree. It maygrow upwards or downwards. How would you characterize/parametrize sizeof a tree.

• Depth of the tree d .

• Max-Depth of the treem. Can be ∞.

• Branching factor b.

• s denotes theshallowest Goal.

• How many nodes inthe whole tree?

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 59: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Search (algorithm) properties

I Guaranteed to find a solution (if exists)? Complete?

I Guaranteed to find the least cost path? Optimal?

I How many steps - an operation with a node? Time complexity?

I How many nodes to remember? Space/Memory complexity?

How many nodes in a tree? What are tree parameters?

15 / 33

Draw a (symbolic–think about a triangle) sketch of a (search) tree. It maygrow upwards or downwards. How would you characterize/parametrize sizeof a tree.

• Depth of the tree d .

• Max-Depth of the treem. Can be ∞.

• Branching factor b.

• s denotes theshallowest Goal.

• How many nodes inthe whole tree?

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 60: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Strategies

How to traverse/build a search tree?

16 / 33

It is perhaps worth to remember that the search tree is built as the algo-

rithm goes. Or better said, the tree is a human friendly representaion of

the machine run.

Page 61: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Depth-First Search (DFS)

a

S

b

c

d

e

f

G

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

What are the DFS properties (complete, optimal, time, space)?

17 / 33

• In animation, we will do the expansion step at once.

• What is the frontier - set of nodes, waiting to be expanded?

• When to stop the search?

• Thinking about optimality, what is the best solution we seek?

Page 62: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Depth-First Search (DFS)

a

S

b

c

d

e

f

G

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

What are the DFS properties (complete, optimal, time, space)?

17 / 33

• In animation, we will do the expansion step at once.

• What is the frontier - set of nodes, waiting to be expanded?

• When to stop the search?

• Thinking about optimality, what is the best solution we seek?

Page 63: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Depth-First Search (DFS)

a

S

b

c

d

e

f

G

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

What are the DFS properties (complete, optimal, time, space)?

17 / 33

• In animation, we will do the expansion step at once.

• What is the frontier - set of nodes, waiting to be expanded?

• When to stop the search?

• Thinking about optimality, what is the best solution we seek?

Page 64: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Depth-First Search (DFS)

a

S

b

c

d

e

f

G

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

What are the DFS properties (complete, optimal, time, space)?

17 / 33

• In animation, we will do the expansion step at once.

• What is the frontier - set of nodes, waiting to be expanded?

• When to stop the search?

• Thinking about optimality, what is the best solution we seek?

Page 65: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Depth-First Search (DFS)

a

S

b

c

d

e

f

G

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

What are the DFS properties (complete, optimal, time, space)?

17 / 33

• In animation, we will do the expansion step at once.

• What is the frontier - set of nodes, waiting to be expanded?

• When to stop the search?

• Thinking about optimality, what is the best solution we seek?

Page 66: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Depth-First Search (DFS)

a

S

b

c

d

e

f

G

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

What are the DFS properties (complete, optimal, time, space)?

17 / 33

• In animation, we will do the expansion step at once.

• What is the frontier - set of nodes, waiting to be expanded?

• When to stop the search?

• Thinking about optimality, what is the best solution we seek?

Page 67: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Depth-First Search (DFS)

a

S

b

c

d

e

f

G

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

What are the DFS properties (complete, optimal, time, space)?

17 / 33

• In animation, we will do the expansion step at once.

• What is the frontier - set of nodes, waiting to be expanded?

• When to stop the search?

• Thinking about optimality, what is the best solution we seek?

Page 68: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Depth-First Search (DFS)

a

S

b

c

d

e

f

G

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

What are the DFS properties (complete, optimal, time, space)?

17 / 33

• In animation, we will do the expansion step at once.

• What is the frontier - set of nodes, waiting to be expanded?

• When to stop the search?

• Thinking about optimality, what is the best solution we seek?

Page 69: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Depth-First Search (DFS)

a

S

b

c

d

e

f

G

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

What are the DFS properties (complete, optimal, time, space)?

17 / 33

• In animation, we will do the expansion step at once.

• What is the frontier - set of nodes, waiting to be expanded?

• When to stop the search?

• Thinking about optimality, what is the best solution we seek?

Page 70: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Depth-First Search (DFS)

a

S

b

c

d

e

f

G

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

What are the DFS properties (complete, optimal, time, space)?

17 / 33

• In animation, we will do the expansion step at once.

• What is the frontier - set of nodes, waiting to be expanded?

• When to stop the search?

• Thinking about optimality, what is the best solution we seek?

Page 71: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Depth-First Search (DFS)

a

S

b

c

d

e

f

G

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

What are the DFS properties (complete, optimal, time, space)?

17 / 33

• In animation, we will do the expansion step at once.

• What is the frontier - set of nodes, waiting to be expanded?

• When to stop the search?

• Thinking about optimality, what is the best solution we seek?

Page 72: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS properties

I Time complexity?

I Space complexity?

I Complete?

I Optimal?

a

S

b

c

d

e

f

G

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

18 / 33

• Time, can process the whole tree: bm

• Space, only the path so far: bm

• Completness: m may be ∞ hence, not in general

• Optimality: No! It just takes the first solution found.

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 73: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS properties

I Time complexity?

I Space complexity?

I Complete?

I Optimal?

a

S

b

c

d

e

f

G

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

18 / 33

• Time, can process the whole tree: bm

• Space, only the path so far: bm

• Completness: m may be ∞ hence, not in general

• Optimality: No! It just takes the first solution found.

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 74: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS properties

I Time complexity?

I Space complexity?

I Complete?

I Optimal?

a

S

b

c

d

e

f

G

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

18 / 33

• Time, can process the whole tree: bm

• Space, only the path so far: bm

• Completness: m may be ∞ hence, not in general

• Optimality: No! It just takes the first solution found.

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 75: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS properties

I Time complexity?

I Space complexity?

I Complete?

I Optimal?

a

S

b

c

d

e

f

G

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

18 / 33

• Time, can process the whole tree: bm

• Space, only the path so far: bm

• Completness: m may be ∞ hence, not in general

• Optimality: No! It just takes the first solution found.

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 76: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS properties

I Time complexity?

I Space complexity?

I Complete?

I Optimal?

a

S

b

c

d

e

f

G

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

18 / 33

• Time, can process the whole tree: bm

• Space, only the path so far: bm

• Completness: m may be ∞ hence, not in general

• Optimality: No! It just takes the first solution found.

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 77: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS properties

I Time complexity?

I Space complexity?

I Complete?

I Optimal?

a

S

b

c

d

e

f

G

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

18 / 33

• Time, can process the whole tree: bm

• Space, only the path so far: bm

• Completness: m may be ∞ hence, not in general

• Optimality: No! It just takes the first solution found.

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 78: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS properties

I Time complexity?

I Space complexity?

I Complete?

I Optimal?

a

S

b

c

d

e

f

G

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

18 / 33

• Time, can process the whole tree: bm

• Space, only the path so far: bm

• Completness: m may be ∞ hence, not in general

• Optimality: No! It just takes the first solution found.

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 79: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS properties

I Time complexity?

I Space complexity?

I Complete?

I Optimal?

a

S

b

c

d

e

f

G

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

18 / 33

• Time, can process the whole tree: bm

• Space, only the path so far: bm

• Completness: m may be ∞ hence, not in general

• Optimality: No! It just takes the first solution found.

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 80: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS properties

I Time complexity?

I Space complexity?

I Complete?

I Optimal?

a

S

b

c

d

e

f

G

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

18 / 33

• Time, can process the whole tree: bm

• Space, only the path so far: bm

• Completness: m may be ∞ hence, not in general

• Optimality: No! It just takes the first solution found.

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 81: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS properties

I Time complexity?

I Space complexity?

I Complete?

I Optimal?

a

S

b

c

d

e

f

G

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

18 / 33

• Time, can process the whole tree: bm

• Space, only the path so far: bm

• Completness: m may be ∞ hence, not in general

• Optimality: No! It just takes the first solution found.

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 82: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Breadth-First Search (BFS)

a

S

b

c

d

e

f

G

S

a

b e

c

f b d

d

G

What are the BFS properties?

19 / 33

Page 83: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Breadth-First Search (BFS)

a

S

b

c

d

e

f

G

S

a

b e

c

f b d

d

G

What are the BFS properties?

19 / 33

Page 84: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Breadth-First Search (BFS)

a

S

b

c

d

e

f

G

S

a

b e

c

f b d

d

G

What are the BFS properties?

19 / 33

Page 85: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Breadth-First Search (BFS)

a

S

b

c

d

e

f

G

S

a

b e

c

f b d

d

G

What are the BFS properties?

19 / 33

Page 86: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Breadth-First Search (BFS)

a

S

b

c

d

e

f

G

S

a

b e

c

f b d

d

G

What are the BFS properties?

19 / 33

Page 87: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Breadth-First Search (BFS)

a

S

b

c

d

e

f

G

S

a

b e

c

f b d

d

G

What are the BFS properties?

19 / 33

Page 88: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

BFS properties

I Time complexity?

I Space complexity?

I Complete?

I Optimal?

a

S

b

c

d

e

f

G

S

a

b e

c

f b d

d

G

20 / 33

• Time, can process the whole tree until s: bs , well actuallyb + b2 + b3 + · · ·+ bs but the last layer vastly dominates. Try somecalculations for various b.

• Space, all the frontier: bs

• Completness: Yes!

• Optimality, it does not miss the shallowest solution, hence if all thetransition costs are 1: Yes!

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 89: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

BFS properties

I Time complexity?

I Space complexity?

I Complete?

I Optimal?

a

S

b

c

d

e

f

G

S

a

b e

c

f b d

d

G

20 / 33

• Time, can process the whole tree until s: bs , well actuallyb + b2 + b3 + · · ·+ bs but the last layer vastly dominates. Try somecalculations for various b.

• Space, all the frontier: bs

• Completness: Yes!

• Optimality, it does not miss the shallowest solution, hence if all thetransition costs are 1: Yes!

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 90: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

BFS properties

I Time complexity?

I Space complexity?

I Complete?

I Optimal?

a

S

b

c

d

e

f

G

S

a

b e

c

f b d

d

G

20 / 33

• Time, can process the whole tree until s: bs , well actuallyb + b2 + b3 + · · ·+ bs but the last layer vastly dominates. Try somecalculations for various b.

• Space, all the frontier: bs

• Completness: Yes!

• Optimality, it does not miss the shallowest solution, hence if all thetransition costs are 1: Yes!

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 91: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

BFS properties

I Time complexity?

I Space complexity?

I Complete?

I Optimal?

a

S

b

c

d

e

f

G

S

a

b e

c

f b d

d

G

20 / 33

• Time, can process the whole tree until s: bs , well actuallyb + b2 + b3 + · · ·+ bs but the last layer vastly dominates. Try somecalculations for various b.

• Space, all the frontier: bs

• Completness: Yes!

• Optimality, it does not miss the shallowest solution, hence if all thetransition costs are 1: Yes!

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 92: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

BFS properties

I Time complexity?

I Space complexity?

I Complete?

I Optimal?

a

S

b

c

d

e

f

G

S

a

b e

c

f b d

d

G

20 / 33

• Time, can process the whole tree until s: bs , well actuallyb + b2 + b3 + · · ·+ bs but the last layer vastly dominates. Try somecalculations for various b.

• Space, all the frontier: bs

• Completness: Yes!

• Optimality, it does not miss the shallowest solution, hence if all thetransition costs are 1: Yes!

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 93: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS vs BFS

What are (dis)advantages of the individual strategies?

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

S

a

b e

c

f b d

d

G

21 / 33

• Do not overfit your thinking!

• Draw for yourself a different graph and contruct appropriate trees.

• Not everything is visible from the animations.

• Draw a comparison tables.

Page 94: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS vs BFS

What are (dis)advantages of the individual strategies?

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

S

a

b e

c

f b d

d

G

21 / 33

• Do not overfit your thinking!

• Draw for yourself a different graph and contruct appropriate trees.

• Not everything is visible from the animations.

• Draw a comparison tables.

Page 95: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS vs BFS

What are (dis)advantages of the individual strategies?

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

S

a

b e

c

f b d

d

G

21 / 33

• Do not overfit your thinking!

• Draw for yourself a different graph and contruct appropriate trees.

• Not everything is visible from the animations.

• Draw a comparison tables.

Page 96: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS vs BFS

What are (dis)advantages of the individual strategies?

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

S

a

b e

c

f b d

d

G

21 / 33

• Do not overfit your thinking!

• Draw for yourself a different graph and contruct appropriate trees.

• Not everything is visible from the animations.

• Draw a comparison tables.

Page 97: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS vs BFS

What are (dis)advantages of the individual strategies?

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

S

a

b e

c

f b d

d

G

21 / 33

• Do not overfit your thinking!

• Draw for yourself a different graph and contruct appropriate trees.

• Not everything is visible from the animations.

• Draw a comparison tables.

Page 98: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS vs BFS

What are (dis)advantages of the individual strategies?

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

S

a

b e

c

f b d

d

G

21 / 33

• Do not overfit your thinking!

• Draw for yourself a different graph and contruct appropriate trees.

• Not everything is visible from the animations.

• Draw a comparison tables.

Page 99: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS vs BFS

What are (dis)advantages of the individual strategies?

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

S

a

b e

c

f b d

d

G

21 / 33

• Do not overfit your thinking!

• Draw for yourself a different graph and contruct appropriate trees.

• Not everything is visible from the animations.

• Draw a comparison tables.

Page 100: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS vs BFS

What are (dis)advantages of the individual strategies?

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

S

a

b e

c

f b d

d

G

21 / 33

• Do not overfit your thinking!

• Draw for yourself a different graph and contruct appropriate trees.

• Not everything is visible from the animations.

• Draw a comparison tables.

Page 101: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS vs BFS

What are (dis)advantages of the individual strategies?

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

S

a

b e

c

f b d

d

G

21 / 33

• Do not overfit your thinking!

• Draw for yourself a different graph and contruct appropriate trees.

• Not everything is visible from the animations.

• Draw a comparison tables.

Page 102: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS vs BFS

What are (dis)advantages of the individual strategies?

S

a

b

e

f

f

e

f

c

f b

e

f

f

d

G

d

S

a

b e

c

f b d

d

G

21 / 33

• Do not overfit your thinking!

• Draw for yourself a different graph and contruct appropriate trees.

• Not everything is visible from the animations.

• Draw a comparison tables.

Page 103: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS with limited depth, maxdepth=2

Do not follow nodes with depth > maxdepth

a

S

b

c

d

e

f

G

S

a

b

e f

e

f

c

f d

G

d

G

22 / 33

Page 104: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS with limited depth, maxdepth=2

Do not follow nodes with depth > maxdepth

a

S

b

c

d

e

f

G

S

a

b

e f

e

f

c

f d

G

d

G

22 / 33

Page 105: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS with limited depth, maxdepth=2

Do not follow nodes with depth > maxdepth

a

S

b

c

d

e

f

G

S

a

b

e f

e

f

c

f d

G

d

G

22 / 33

Page 106: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS with limited depth, maxdepth=2

Do not follow nodes with depth > maxdepth

a

S

b

c

d

e

f

G

S

a

b

e f

e

f

c

f d

G

d

G

22 / 33

Page 107: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS with limited depth, maxdepth=2

Do not follow nodes with depth > maxdepth

a

S

b

c

d

e

f

G

S

a

b

e f

e

f

c

f d

G

d

G

22 / 33

Page 108: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS with limited depth, maxdepth=2

Do not follow nodes with depth > maxdepth

a

S

b

c

d

e

f

G

S

a

b

e f

e

f

c

f d

G

d

G

22 / 33

Page 109: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS with limited depth, maxdepth=2

Do not follow nodes with depth > maxdepth

a

S

b

c

d

e

f

G

S

a

b

e f

e

f

c

f d

G

d

G

22 / 33

Page 110: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

DFS with limited depth, maxdepth=2

Do not follow nodes with depth > maxdepth

a

S

b

c

d

e

f

G

S

a

b

e f

e

f

c

f d

G

d

G

22 / 33

Page 111: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Iterative deepening DFS (ID-DFS)

I Start with maxdepth = 1

I Perform DFS with limited depth. Report success or failure.

I If failure, forget everything, increase maxdepth and repeat DFS

Is it not a terrible waste to forget everything between steps?

23 / 33

Really, how much do we repeat/waste? Compare number fo nodes gener-ated ID-DFS vs. BFS:

N(ID-DFS) = (s)b + (s − 1)b2 + (s − 2)b3 + · · ·+ (1)bs

N(BFS) = b + b2 + b3 + · · ·+ bs

Try some calculations for various s and b.

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 112: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Iterative deepening DFS (ID-DFS)

I Start with maxdepth = 1

I Perform DFS with limited depth. Report success or failure.

I If failure, forget everything, increase maxdepth and repeat DFS

Is it not a terrible waste to forget everything between steps?

23 / 33

Really, how much do we repeat/waste? Compare number fo nodes gener-ated ID-DFS vs. BFS:

N(ID-DFS) = (s)b + (s − 1)b2 + (s − 2)b3 + · · ·+ (1)bs

N(BFS) = b + b2 + b3 + · · ·+ bs

Try some calculations for various s and b.

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 113: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Iterative deepening DFS (ID-DFS)

I Start with maxdepth = 1

I Perform DFS with limited depth. Report success or failure.

I If failure, forget everything, increase maxdepth and repeat DFS

Is it not a terrible waste to forget everything between steps?

23 / 33

Really, how much do we repeat/waste? Compare number fo nodes gener-ated ID-DFS vs. BFS:

N(ID-DFS) = (s)b + (s − 1)b2 + (s − 2)b3 + · · ·+ (1)bs

N(BFS) = b + b2 + b3 + · · ·+ bs

Try some calculations for various s and b.

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 114: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Iterative deepening DFS (ID-DFS)

I Start with maxdepth = 1

I Perform DFS with limited depth. Report success or failure.

I If failure, forget everything, increase maxdepth and repeat DFS

Is it not a terrible waste to forget everything between steps?

23 / 33

Really, how much do we repeat/waste? Compare number fo nodes gener-ated ID-DFS vs. BFS:

N(ID-DFS) = (s)b + (s − 1)b2 + (s − 2)b3 + · · ·+ (1)bs

N(BFS) = b + b2 + b3 + · · ·+ bs

Try some calculations for various s and b.

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 115: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Cost sensitive search

a

S

b

c

d

e

f

G

1

3

1

1

2

1

1

1

1

1

1

1.5S,0

a,1

b,2 e,2

c,1

f,2 b,2 d,2

d,1

G,2

I In BFS, DFS, node ±depth was thenode-value.

I How was the depth actually computed?

I How to evaluate nodes with path cost?

24 / 33

Page 116: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Cost sensitive search

a

S

b

c

d

e

f

G

1

3

1

1

2

1

1

1

1

1

1

1.5S,0

a,1

b,2 e,2

c,1

f,2 b,2 d,2

d,1

G,2

I In BFS, DFS, node ±depth was thenode-value.

I How was the depth actually computed?

I How to evaluate nodes with path cost?

24 / 33

Page 117: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Cost sensitive search

a

S

b

c

d

e

f

G

1

3

1

1

2

1

1

1

1

1

1

1.5S,0

a,1

b,2 e,2

c,1

f,2 b,2 d,2

d,1

G,2

I In BFS, DFS, node ±depth was thenode-value.

I How was the depth actually computed?

I How to evaluate nodes with path cost?

24 / 33

Page 118: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Cost sensitive search

a

S

b

c

d

e

f

G

1

3

1

1

2

1

1

1

1

1

1

1.5S,0

a,1

b,2 e,2

c,1

f,2 b,2 d,2

d,1

G,2

I In BFS, DFS, node ±depth was thenode-value.

I How was the depth actually computed?

I How to evaluate nodes with path cost?

24 / 33

Page 119: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Uniform Cost Search (UCS)

a

S

b

c

d

e

f

G

1

3

1

1

2

1

1

1

1

1

1

1.5S,0

a,1

b,2

e,3 f,4

e,2.5

c,1

f,2 b,2 d,2

G,3

d,3

When to check the goal (and stop) the search? When visiting orexpanding the node?

25 / 33

Page 120: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Uniform Cost Search (UCS)

a

S

b

c

d

e

f

G

1

3

1

1

2

1

1

1

1

1

1

1.5S,0

a,1

b,2

e,3 f,4

e,2.5

c,1

f,2 b,2 d,2

G,3

d,3

When to check the goal (and stop) the search? When visiting orexpanding the node?

25 / 33

Page 121: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Uniform Cost Search (UCS)

a

S

b

c

d

e

f

G

1

3

1

1

2

1

1

1

1

1

1

1.5S,0

a,1

b,2

e,3 f,4

e,2.5

c,1

f,2 b,2 d,2

G,3

d,3

When to check the goal (and stop) the search? When visiting orexpanding the node?

25 / 33

Page 122: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Uniform Cost Search (UCS)

a

S

b

c

d

e

f

G

1

3

1

1

2

1

1

1

1

1

1

1.5S,0

a,1

b,2

e,3 f,4

e,2.5

c,1

f,2 b,2 d,2

G,3

d,3

When to check the goal (and stop) the search? When visiting orexpanding the node?

25 / 33

Page 123: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Uniform Cost Search (UCS)

a

S

b

c

d

e

f

G

1

3

1

1

2

1

1

1

1

1

1

1.5S,0

a,1

b,2

e,3 f,4

e,2.5

c,1

f,2 b,2 d,2

G,3

d,3

When to check the goal (and stop) the search? When visiting orexpanding the node?

25 / 33

Page 124: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Uniform Cost Search (UCS)

a

S

b

c

d

e

f

G

1

3

1

1

2

1

1

1

1

1

1

1.5S,0

a,1

b,2

e,3 f,4

e,2.5

c,1

f,2 b,2 d,2

G,3

d,3

When to check the goal (and stop) the search? When visiting orexpanding the node?

25 / 33

Page 125: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Uniform Cost Search (UCS)

a

S

b

c

d

e

f

G

1

3

1

1

2

1

1

1

1

1

1

1.5S,0

a,1

b,2

e,3 f,4

e,2.5

c,1

f,2 b,2 d,2

G,3

d,3

When to check the goal (and stop) the search? When visiting orexpanding the node?

25 / 33

Page 126: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

When to stop, when visiting or expanding?

a

S

b

c

d

e

f

G

1

3

1

1

2

1

1

11.2

0.5

1

1

1

1.5S,0

a,1

b,2

e,3 f,4

e,2.5

f,3

c,1

f,2.2

G,2.7

d,2

G,3

b,2

e,3 f,4

d,3

26 / 33

Page 127: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

When to stop, when visiting or expanding?

a

S

b

c

d

e

f

G

1

3

1

1

2

1

1

11.2

0.5

1

1

1

1.5S,0

a,1

b,2

e,3 f,4

e,2.5

f,3

c,1

f,2.2

G,2.7

d,2

G,3

b,2

e,3 f,4

d,3

26 / 33

Page 128: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

When to stop, when visiting or expanding?

a

S

b

c

d

e

f

G

1

3

1

1

2

1

1

11.2

0.5

1

1

1

1.5S,0

a,1

b,2

e,3 f,4

e,2.5

f,3

c,1

f,2.2

G,2.7

d,2

G,3

b,2

e,3 f,4

d,3

26 / 33

Page 129: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

When to stop, when visiting or expanding?

a

S

b

c

d

e

f

G

1

3

1

1

2

1

1

11.2

0.5

1

1

1

1.5S,0

a,1

b,2

e,3 f,4

e,2.5

f,3

c,1

f,2.2

G,2.7

d,2

G,3

b,2

e,3 f,4

d,3

26 / 33

Page 130: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

When to stop, when visiting or expanding?

a

S

b

c

d

e

f

G

1

3

1

1

2

1

1

11.2

0.5

1

1

1

1.5S,0

a,1

b,2

e,3 f,4

e,2.5

f,3

c,1

f,2.2

G,2.7

d,2

G,3

b,2

e,3 f,4

d,3

26 / 33

Page 131: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

When to stop, when visiting or expanding?

a

S

b

c

d

e

f

G

1

3

1

1

2

1

1

11.2

0.5

1

1

1

1.5S,0

a,1

b,2

e,3 f,4

e,2.5

f,3

c,1

f,2.2

G,2.7

d,2

G,3

b,2

e,3 f,4

d,3

26 / 33

Page 132: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

When to stop, when visiting or expanding?

a

S

b

c

d

e

f

G

1

3

1

1

2

1

1

11.2

0.5

1

1

1

1.5S,0

a,1

b,2

e,3 f,4

e,2.5

f,3

c,1

f,2.2

G,2.7

d,2

G,3

b,2

e,3 f,4

d,3

26 / 33

Page 133: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

When to stop, when visiting or expanding?

a

S

b

c

d

e

f

G

1

3

1

1

2

1

1

11.2

0.5

1

1

1

1.5S,0

a,1

b,2

e,3 f,4

e,2.5

f,3

c,1

f,2.2

G,2.7

d,2

G,3

b,2

e,3 f,4

d,3

26 / 33

Page 134: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

When to stop, when visiting or expanding?

a

S

b

c

d

e

f

G

1

3

1

1

2

1

1

11.2

0.5

1

1

1

1.5S,0

a,1

b,2

e,3 f,4

e,2.5

f,3

c,1

f,2.2

G,2.7

d,2

G,3

b,2

e,3 f,4

d,3

26 / 33

Page 135: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

When to stop, when visiting or expanding?

a

S

b

c

d

e

f

G

1

3

1

1

2

1

1

11.2

0.5

1

1

1

1.5S,0

a,1

b,2

e,3 f,4

e,2.5

f,3

c,1

f,2.2

G,2.7

d,2

G,3

b,2

e,3 f,4

d,3

26 / 33

Page 136: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

When to stop, when visiting or expanding?

a

S

b

c

d

e

f

G

1

3

1

1

2

1

1

11.2

0.5

1

1

1

1.5S,0

a,1

b,2

e,3 f,4

e,2.5

f,3

c,1

f,2.2

G,2.7

d,2

G,3

b,2

e,3 f,4

d,3

26 / 33

Page 137: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

UCS properties

I Time complexity?

I Space complexity?

I Complete?

I Optimal?

S,0

a,1

b,2

e,3 f,4

e,2.5

f,3

c,1

f,2.2

G,2.7

d,2

G,3

b,2

e,3 f,4

d,3

27 / 33

Solution cost C∗, transition cost at least ε. Effective depth, roughly C∗/ε.

• Time: bC∗/ε

• Space: bC∗/ε

• Completness: Yes!

• Optimality: Yes! Why?

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 138: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

UCS properties

I Time complexity?

I Space complexity?

I Complete?

I Optimal?

S,0

a,1

b,2

e,3 f,4

e,2.5

f,3

c,1

f,2.2

G,2.7

d,2

G,3

b,2

e,3 f,4

d,3

27 / 33

Solution cost C∗, transition cost at least ε. Effective depth, roughly C∗/ε.

• Time: bC∗/ε

• Space: bC∗/ε

• Completness: Yes!

• Optimality: Yes! Why?

m<latexit sha1_base64="4Gt0MY3yLD/OalBm/rL7VXeHCpc=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVTda6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCWrApDw=</latexit>

1 node<latexit sha1_base64="jHZBbUzr1Fh9bD4SkqNLpPYDO5A=">AAACKXicZVDLSgNBEJz1GeMr0aOXwSh4Crt60GPQi8cIxgSyQXpne3VwHsvMrBKW/IRX/QO/xpt69UecxIivhoaiqhuqKskFty4MX4OZ2bn5hcXKUnV5ZXVtvVbfuLC6MAw7TAtteglYFFxhx3EnsJcbBJkI7CY3J2O9e4vGcq3O3TDHgYQrxTPOwHmqtxPtUKVTvKw1wmY4GfofRFPQINNpX9aD5TjVrJCoHBNgbT8KczcowTjOBI6qcWExB3YDV9j3UIFEOygnhkd01zMpzbTxqxydsD8/SpDWDmXiLyW4a/tXG5PfmkGFd0xLCSot4wwkF8MUMyiEG5Wxzb7wb08uOxqUXOWFQ8U+LWWFoE7TcU805QaZE0MPgBnuU1F2DQaY821W4xwMV6kPT33sqq8v+lvWf3Cx34wOmuHZfqN1PC2yQrbINtkjETkkLXJK2qRDGBHknjyQx+ApeA5egrfP05lg+rNJfk3w/gHYRKX4</latexit>

b nodes<latexit sha1_base64="X/txyhIIuDx49R6RKr7nMT/tLWE=">AAACKnicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eFQwJpINoXe2VwfnsczMKmHJV3jVP/BrvIlXP8RJjKhJQ0NR1Q1VleSCWxeG78HM7Nz8wmJlqbq8srq2vlHbvLa6MAybTAtt2glYFFxh03EnsJ0bBJkIbCX3Z0O99YDGcq2uXD/HroRbxTPOwHnqZjfZpUqnaHsb9bARjoZOg2gM6mQ8F71asBynmhUSlWMCrO1EYe66JRjHmcBBNS4s5sDu4RY7HiqQaLvlyPGA7nkmpZk2fpWjI/bvRwnS2r5M/KUEd2cntSH5qxlU+Mi0lKDSMs5ActFPMYNCuEEZ2+wH//fksuNuyVVeOFTs21JWCOo0HRZFU26QOdH3AJjhPhVld2CAOV9nNc7BcJX68NTHrvr6osmypsH1QSM6bISXB/WT03GRFbJNdsg+icgROSHn5II0CSOSPJFn8hK8Bm/Be/DxfToTjH+2yL8JPr8AHtympg==</latexit>

b2 nodes<latexit sha1_base64="ZGTW0YYeXQcbuGbIvHUVnYaFmjc=">AAACLHicZVDLSgNBEJyN7/iKevQyGAVPYTce9Ch68ahgVMhG6Z3t1SHzWGZmlbDkM7zqH/g1XkS8+h1OYkQTGxqKqm6oqiQX3LowfAsqU9Mzs3PzC9XFpeWV1dra+oXVhWHYYlpoc5WARcEVthx3Aq9ygyATgZdJ93igX96jsVyrc9fLsSPhVvGMM3Ceam8n181tqnSK9qZWDxvhcOh/EI1AnYzm9GYtWIxTzQqJyjEB1rajMHedEozjTGC/GhcWc2BduMW2hwok2k459NynO55JaaaNX+XokP37UYK0ticTfynB3dlJbUD+agYVPjAtJai0jDOQXPRSzKAQrl/GNvvB455cdtApucoLh4p9W8oKQZ2mg6poyg0yJ3oeADPcp6LsDgww5wutxjkYrlIfnvrYVV9fNFnWf3DRbER7jfCsWT88GhU5TzbJFtklEdknh+SEnJIWYUSTR/JEnoOX4DV4Dz6+TyvB6GeDjE3w+QVpg6dK</latexit>

bm nodes<latexit sha1_base64="psCuRV1mt1LvxYwyneuj19UIUhU=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kSm5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9Hqp4U=</latexit>

…………………

s<latexit sha1_base64="r8gbB3BUNfto6YMSFfYvarzt09Y=">AAACJHicZVDLSgNBEJz1GeMzevQymAiewq4e9Ch68RjRJIIbQu9sbzJkZnaZmVXCkk/wqn/g13gTD178FicP8dXQUFR1Q1VFmeDG+v67Nze/sLi0XFopr66tb2xuVbZbJs01wyZLRapvIjAouMKm5VbgTaYRZCSwHQ3Ox3r7DrXhqbq2www7EnqKJ5yBddRVzdS6W1W/7k+G/gfBDFTJbBrdircaxinLJSrLBBhzG/iZ7RSgLWcCR+UwN5gBG0APbx1UINF0ionXEd13TEyTVLtVlk7Ynx8FSGOGMnKXEmzf/NXG5LemUeE9S6UEFRdhApKLYYwJ5MKOitAkX/i3J5ucdAqustyiYlNLSS6oTem4IhpzjcyKoQPANHepKOuDBmZdkeUwA81V7MJTF7vs6gv+lvUftA7rwVHdvzysnp7NiiyRXbJHDkhAjskpuSAN0iSM9MgDeSRP3rP34r16b9PTOW/2s0N+jffxCXU6pEI=</latexit> bs nodes<latexit sha1_base64="kR75eygmGA/ulNW+P3CFg39Zu38=">AAACLHicZVDLSgNBEJz1GeMzevQyGAVPYVcPehS9eIxgNJCN0jvbq4PzWGZmlbDkM7zqH/g1XkS8+h1OHqLRhoaiqhuqKskFty4M34Kp6ZnZufnKQnVxaXllda22fmF1YRi2mBbatBOwKLjCluNOYDs3CDIReJncnQz0y3s0lmt17no5diXcKJ5xBs5Tne3kym5TpVO012v1sBEOh/4H0RjUyXia17VgMU41KyQqxwRY24nC3HVLMI4zgf1qXFjMgd3BDXY8VCDRdsuh5z7d8UxKM238KkeH7O+PEqS1PZn4Swnu1v7VBuSPZlDhA9NSgkrLOAPJRS/FDArh+mVss2886cllh92Sq7xwqNjIUlYI6jQdVEVTbpA50fMAmOE+FWW3YIA5X2g1zsFwlfrw1Meu+vqiv2X9Bxd7jWi/EZ7t1Y+Ox0VWyCbZIrskIgfkiJySJmkRRjR5JE/kOXgJXoP34GN0OhWMfzbIxASfX9yIp4s=</latexit>

Page 139: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Example: Graph with costs

Uniform#Cost#Search#

S

a

b

d p

a

c

e

p

h

f

r

q

q c G

a

q e

p

h

f

r

q

q c G

a

Strategy: expand a cheapest node first:

Fringe is a priority queue (priority: cumulative cost) S

G

d

b

p q

c

e

h

a

f

r

3 9 1

16 4 11

5

7 13

8

10 11

17 11

0

6

3 9

1

1

2

8

8 2

15

1

2

Cost contours

2

28 / 33

Try it on paper, mark which nodes are in frontier, mark lines of equal cost.

Page 140: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Programming a Tree Search

29 / 33

Page 141: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Infrastructure for (tree) search algorithms

What should a tree node n now?

I n.state

I n.parent

I n.pathcost

Perhaps we may add something later, if needed . . .

30 / 33

Page 142: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

Infrastructure for (tree) search algorithms

What should a tree node n now?

I n.state

I n.parent

I n.pathcost

Perhaps we may add something later, if needed . . .

30 / 33

Page 143: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

How to organize nodes?

The Python examples are just suggestions, . . .

I A dynamically linked structure (list()).

I Add a node (list.insert(node)).

I Take a node and remove from the structure (node=list.pop()).

I Check the Python modules heapq1 and queue2 for inspiration.

1https://docs.python.org/3.5/library/heapq.html2https://docs.python.org/3.5/library/queue.html

31 / 33

Page 144: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

What is the solution?

I We stop when Goal is reached.

I How do we contruct the path?

32 / 33

Page 145: Problem solving by search - cw.fel.cvut.cz fileSequence of cities (path) Giurgiu Urziceni Hirsova Eforie Neamt Oradea Zerind Arad Timisoara Lugoj Mehadia Dobreta Craiova Sibiu Fagaras

References

Some figures if from [1].

[1] Stuart Russell and Peter Norvig.Artificial Intelligence: A Modern Approach.Prentice Hall, 3rd edition, 2010.http://aima.cs.berkeley.edu/.

33 / 33