Introduction to
Data Structure
www.eshikshak.co.in
Algorithm● An algorithm is a finite set of instructions
which, when followed, accomplishes a particular task.
● Its Characteristics ○ Each instruction should be unique and concise○ Each instruction should be relative in nature
and should not be repeated infinitely.○ Repetition of same task(s) should be avoided.○ The result be available to the user after the
algorithm terminates.
www.eshikshak.co.in
Efficiency of Algorithms● The performance of algorithms can be
measured on the scales
● Time● Space
www.eshikshak.co.in
Space Complexity● The amount of memory space required by the
algorithm during the course of execution● Some of the reasons for space complexity are
○ If the program, is to run on mutli-user system, it may be required to specify the amount of memory to be allocated to the program
○ We may be interested to know in advance that whether sufficient memory is available to run the program.
○ There may be several possible solutions with different space requirements.
www.eshikshak.co.in
Space needed by Program Components
● Instruction Space – Space needed to store the executable version of the program and it is fixed.
● Data Space : It is needed to store all constants, varialbe values
● Environment Space : Space needed to store the information needed to resume the suspended functions.
www.eshikshak.co.in
Time Complexity● The amount of time needed to run to
completion.● Some reasons for studying time
complexity○ We may be interested to know in
advance that whether a program will provide satisfactory real time response.
○ There must be several possible solutions with different time requirements.
www.eshikshak.co.in
Data structure ● When elements of data are organized together in
terms of some relationships among the elements, the organization is called data structure.
● A data structure is a set of data values along with the relationship between the data values in form of set of operations permitted on them.
● Arrays, records, stacks, lists, graphs are the names of some of some of these basic data structures.
www.eshikshak.co.in
A data structure can be(a) transienti.e. it is created when a program starts and is destroyed when the program ends. Most data structures in main memory are transient, for example, an array of data.
(b) Permanenti.e. it already exists when a program starts and is preserved when the program ends. Most data structures on disk are permanent, for example, a file of data, or a cross-linked data file collection (a database).
www.eshikshak.co.in
www.eshikshak.co.in
Data Structure
Linear Non-Linear
● Array● Stack● Queue● Linked
Lists
● Tree● Graph
Abstract Data Type (ADT)● It is a mathematical model with a collections of
operations defined on that model.
● The ADT encapsulates a data type can be localized and are not visible to the users of the ADT.
● An implementation of an ADT is a translation into statements of a programming language, of the declaration that defines a variable to be of that ADT, plus a procedure in that language for each operation of the ADT.
www.eshikshak.co.in
Top Related