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

Algorithms, b) The user will roll two (six-sided) dices and the user will l...

b) The user will roll two (six-sided) dices and the user will lose the game if (s)he gets a value 1 on either any of the two dices & wins otherwise. Display a message to the user w

Procedures, what is far and near procedures in system programming?

what is far and near procedures in system programming?

Determine about the post conditions assertion, Determine about the Post con...

Determine about the Post conditions assertion A  post condition is an assertion which should be true at completion of an operation. For instance, a post condition of the squ

Algorithmic implementation of multiple stacks, So far, we now have been con...

So far, we now have been concerned only with the representation of single stack. What happens while a data representation is required for several stacks? Let us consider an array X

Abstract data type- queue, A significant aspect of Abstract Data Types is t...

A significant aspect of Abstract Data Types is that they explain the properties of a data structure without specifying the details of its implementation. The properties might be im

Write an algorithm outputs number of books using psuedocode, A shop sells b...

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

Program, What is a first-in-first-out data structure ? Write algorithms to...

What is a first-in-first-out data structure ? Write algorithms to perform the following operations on it – create, insertion, deletion, for testing overflow and empty conditions.

Define big oh notation, Big oh notation (O) : The upper bound for the funct...

Big oh notation (O) : The upper bound for the function 'f' is given by the big oh notation (O). Considering 'g' to be a function from the non-negative integers to the positive real

Explain optimal binary search trees, Explain Optimal Binary Search Trees ...

Explain Optimal Binary Search Trees One of the principal application of Binary Search Tree is to execute the operation of searching. If probabilities of searching for elements

Bayesian statistics question, Suppose that there is a Beta(2,2) prior distr...

Suppose that there is a Beta(2,2) prior distribution on the probability theta that a coin will yield a "head" when spun in a specified manner. The coin is independently spun 10 tim

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