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

Nothing, c++ To calculate the amount to be paid by a customer buying yummy ...

c++ To calculate the amount to be paid by a customer buying yummy cupcakes for his birth day party

Link list, algorithm for multiplication of two sparse matrices using link l...

algorithm for multiplication of two sparse matrices using link list

Define approximating smooth surfaces with polygon nets, Approximating smoot...

Approximating smooth surfaces with Polygon nets Networks of polygons are used to represent smooth surfaces. They are, of course, only an approximation to the true surface, but

Generic doubly linked list, Your objective is to write a generic doubly lin...

Your objective is to write a generic doubly linked list class called CS228LinkedList that implements the List interface and uses a type variable T. All methods except for subList a

Prims algorithm, how to write prims algorithms? with example

how to write prims algorithms? with example

Difference between array and abstract data types, Difference between array ...

Difference between array and abstract data types Arrays aren't abstract data types since their arrangement in the physical memory of a computer is an essential feature of their

Define prims algorithm, Define Prim's Algorithm Prim's  algorithm  is  ...

Define Prim's Algorithm Prim's  algorithm  is  a  greedy  algorithm  for  constructing  a  minimum  spanning  tree  of  a  weighted linked graph. It works by attaching to a bef

Types of triangular matrices, Triangular Matrices Tiangular Matrices is...

Triangular Matrices Tiangular Matrices is of 2 types: a)  Lower triangular b)  Upper triangular

Relative and direct files, Each data record contains a fixed place in a rel...

Each data record contains a fixed place in a relative file. Each record ought to have associated with it in integer key value which will help identify this slot. Therefore, this ke

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