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

Tree, application of threaded binary treee

application of threaded binary treee

Use of asymptotic notation in the study of algorithm, Q. What is the need o...

Q. What is the need of using asymptotic notation in the study of algorithm? Describe the commonly used asymptotic notations and also give their significance.

Merge sort, Merge sort is a sorting algorithm which uses the basic idea of ...

Merge sort is a sorting algorithm which uses the basic idea of divide and conquers. This algorithm initially divides the array into two halves, sorts them separately and then merge

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

what is far and near procedures in system programming?

Compare and contrast various sorting techniques, Q. Compare and contrast va...

Q. Compare and contrast various sorting techniques or methods with respect to the memory space and the computing time.

Program to implementing stack using linked lists, include include i...

include include include /* Definition of structure node */ typedef struct node { int data; struct node *next; } ; /* Definition of push function */

Shortest path dijkstras algorithm, * Initialise d & pi* for each vertex ...

* Initialise d & pi* for each vertex v within V( g ) g.d[v] := infinity  g.pi[v] := nil g.d[s] := 0; * Set S to empty * S := { 0 }  Q := V(g) * While (V-S)

Ruby implements range of t abstract data type, Ruby implements Range of T A...

Ruby implements Range of T Abstract data type Ruby implements Range of T ADT in its Range class. Elements of carrier set are represented in Range instances by recording interna

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