Lecture 16:

Tree Traversal

Introduction

Tree Traversals

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PREORDER

jenkopbfaclgmdhi

INORDER

jhopkefbclmghida

POSTORDER

Tree Traversal Algorithms

Ordered tree traversals are based on the depth-first graph traversal. The structure of all depth-first tree traversals are the same. The diffence is in when each node is evaluated.

function traverse(node: X){ for (all child nodes Y) { traverse(Y) }}

Permutation Tree for Four Elements

Simple Maze Solving as Tree Traversal

List Representation of a Binary Tree

Edge List Representations of a Tree

Dynamic Memory Representations of a Tree

A General Tree in Dynamic Memory

Data-Tag-Next

Example: Breadth-First Traversal

Breadth-First Traversal of a Treesample Ada Code

Depth-First Traversal - Binary Dreet

Depth-First Traversal of a Tree

Implementing Depth-First Traversals

PREORDER INORDER POSTORDER

Watching the Stack

Summary

DFT Tree TraversalsPre-orderIn-orderPost-order

Permutation Trees

Simple Maze as a Tree

List Representation of a Binary Tree

Edge List Representation of a Tree

Trees in Dynamic Memory

Data-Tag-Next: a general tree node

Breadth-First TraversalsUsually on Permutation TreesIterative with a Queue

Depth-First TraveralsUsed mostly for search and sortRecursive with a Stack