Complexity of an algorithm, Data Structure & Algorithms

Assignment Help:

Q. Explain the complexity of an algorithm?  What are the worst case analysis and best case analysis explain with an example.                                                                                                                

Ans:

The complexity of the algorithm M is the function f(n) which gives the running time or storage space requirement of the algorithm in terms of the size n of the input data. Frequently, the storage space needed by an algorithm is just a multiple of the data size n. Therefore, the term "complexity" should be referring to the running time of the algorithm.

We find the complexity function f(n) for the certain number of cases. The two cases to which one usually investigates in complexity theory are as follows:-
i. The worst case:-  the maximum value of f(n) for any input possible
ii. The best case:-  the least possible value of f(n)

For example:-

Hear if we take an example of linear search in which an integer Item is to searched or found in an array Data. The complexity if the search algorithm is given by number C of comparisons between Item and Data[k].

Worst case:-

The worst case occurs when the Item is last element in the array Data or is it not there at all. In both of these cases, we get

C(n)=n

In the average case, we presume that the Item is present is the array and is likely to be present in any position in the array. Hence the number of comparisons can be any of the numbers 1, 2, 3........n and each number occurs with probability

p = 1/n.

C(n) = 1. 1/n + 2.1/n + ... + n.1/n

= (n+1) / 2

hence the average number of comparisons needed to locate the Item in to array Data is approximately the same to half the number of elements in the Data list.


Related Discussions:- Complexity of an algorithm

Exlain double linked list, Double Linked List In a doubly linked list, ...

Double Linked List In a doubly linked list, also known as 2 way lists, each node is separated into 3 parts. The first part is called last pointer field. It has the address of t

Perform breadth -first search, You are given two jugs, a 4-gallon one and a...

You are given two jugs, a 4-gallon one and a 3-gallon one. Neither has any measuring marker on it. There is a tap that can be used to fill the jugs with water. How can you get exac

Define game trees, Game trees An interesting application of trees is th...

Game trees An interesting application of trees is the playing of games such as tie-tac-toe, chess, nim, kalam, chess, go etc. We can picture the sequence of possible moves by m

Algorithm that inputs the codes for all items in stock, A shop sells books,...

A shop sells books, magazines and maps. Every item is identified by a unique 4 - digit code. All books have a code which starts with 1, all maps have a code starting with 2 and all

Graph search using iterative deepening, Prove that uniform cost search and ...

Prove that uniform cost search and breadth- first search with constant steps are optimal when used with the Graph-Search algorithm (see Figure). Show a state space with varying ste

Doubly linked list having n nodes, The time required to delete a node x fro...

The time required to delete a node x from a doubly linked list having n nodes is O (1)

Sparse metrics, Q. Define the sparse metrics and also explain the represent...

Q. Define the sparse metrics and also explain the representation of a 4X4 matrix using linked list.         Ans: A matrix in which number of zero entries is quite h

Multikey file organization, what are the applications of multikey file orga...

what are the applications of multikey file organization?

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd