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

Decision tree, . Create a decision table that describes the movement of inv...

. Create a decision table that describes the movement of inventory

Illustrate the varieties of arrays, Varieties of Arrays In some languag...

Varieties of Arrays In some languages, size of an array should be established once and for all at program design time and can't change during execution. Such arrays are known a

Determine the importance of array, Determine the importance of array Ar...

Determine the importance of array Arrays are significant since they allow many values to be stored in a single data structure whereas providing very fast access to each value.

Algorithm for linear search, Here,  m represents the unordered array of ele...

Here,  m represents the unordered array of elements n  represents number of elements in the array and el  represents the value to be searched in the list Sep 1: [Initialize]

What is quick sort, What is quick sort? Quick sort is a sorting algorit...

What is quick sort? Quick sort is a sorting algorithm that uses the idea if split and conquer. This algorithm chooses an element called as pivot element; search its position in

Implementation of stack using linked lists, In the last subsection, we have...

In the last subsection, we have implemented a stack by using an array. While a stack is implemented by using arrays, it suffers from the basic restriction of an array - i.e., its s

Implementation of stack, Before programming a problem solution those employ...

Before programming a problem solution those employees a stack, we have to decide how to represent a stack by using the data structures which exist in our programming language. Stac

State flowchart that take temperature input using pseudocode, Write an algo...

Write an algorithm using pseudocode which takes temperatures input over a 100 day period (once per day) and output the number of days when the temperature was below 20C and the num

What is a height balanced tree, What is a height balanced tree? Height Ba...

What is a height balanced tree? Height Balanced Tree (AVL Tree) An AVL tree is a binary search tree in which the height of the left and right subtree of the root vary by at most

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