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

Multiple Queues in a single dimension array, Implement multiple queues in a...

Implement multiple queues in a single dimensional array. Write algorithms for various queue operations for them.

Implementation of stack, Implementation of Stack :- Stacks can be execu...

Implementation of Stack :- Stacks can be executed in the 2 ways: a)  Arrays b)  Linked List

Expression trees, What are the expression trees? Represent the below writte...

What are the expression trees? Represent the below written expression using a tree. Give a relevant comment on the result that you get when this tree is traversed in Preorder,

Depth of complete binary tree, What will be depth do , of complete binary t...

What will be depth do , of complete binary tree of n nodes, where nodes are labelled from 1 to n with root as node and last leaf node as node n

Type of qualitative method, Type of Qualitative Method: Different  qua...

Type of Qualitative Method: Different  qualitative methods are suitable for different  types of study. Quite often we can  combine  qualitative and quantitative  methods. Many

Program for linear search, Program for Linear Search. Program: Linear S...

Program for Linear Search. Program: Linear Search /*Program for Linear Search*/ /*Header Files*/ #include #include /*Global Variables*/ int search; int

Write an algorithm to input number of passengers travelling, There are ten ...

There are ten stations on a railway line: Train travels in both directions (i.e. from 1 to 10 and then from 10 to 1).  Fare between each station is $2. A passenger input

Make adjacency matrix for un-directed graph, Q. Describe the adjacency matr...

Q. Describe the adjacency matrix and make the same for the given undirected graph.    Ans: The representation of Adjacency Matrix: This representation consists of

Red-black tree after insertion, The above 3 cases are also considered conve...

The above 3 cases are also considered conversely while the parent of Z is to the right of its own parent. All the different kind of cases can be illustrated through an instance. Le

Darw a flowchart to input 3 numbers, This algorithm inputs 3 numbers, every...

This algorithm inputs 3 numbers, every number goes through successive division by 10 until its value is less than 1. An output is produced which comprise the number input and a val

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