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

Define about the class invariant, Define about the class invariant A cl...

Define about the class invariant A class invariant may not be true during execution of a public operation though it should be true between executions of public operations. For

Comp. sci algorithms, 1. develop an algorithm which reads two decimal numbe...

1. develop an algorithm which reads two decimal numbers x and y and determines and prints out wether x>y or y>x. the input values, x and y, are whole number > or equal to 0, which

Postfix expression, Ask question Write an algorithm for the evaluation of a...

Ask question Write an algorithm for the evaluation of a postfix expression using a stack#Minimum 100 words accepted#

Last in first out method, This method is the reverse of FIFO and assumes th...

This method is the reverse of FIFO and assumes that each issue of stock is made from latest items received in the enterprises .Thus if the last lot to be received is not sufficient

State hsv colour model, HSV Colour Model Instead of a set of colour pri...

HSV Colour Model Instead of a set of colour primaries, the HSV model uses colour descriptions that have a more intuitive appeal to a user. To give a colour specification, a use

Insertion of element into a linked list, ALGORITHM (Insertion of element in...

ALGORITHM (Insertion of element into a linked list) Step 1 Begin the program Step 2 if the list is empty or any new element comes before the start (head) element, then add t

Asymptotic notation, Asymptotic notation Let us describe a few function...

Asymptotic notation Let us describe a few functions in terms of above asymptotic notation. Example: f(n) = 3n 3 + 2n 2 + 4n + 3 = 3n 3 + 2n 2 + O (n), as 4n + 3 is of

State in brief about assertion, State  in brief about assertion Asser...

State  in brief about assertion Assertion: A statement which should be true at a designated point in a program.

Describe commonly used asymptotic notations, Q.1 Compare two functions n 2 ...

Q.1 Compare two functions n 2 and 2 n for various values of n. Determine when second becomes larger than first. Q.2 Why do we use asymptotic notation in the study of algorit

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