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 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

Explain the rgb model, RGB Model The RGB model is based on the assumpti...

RGB Model The RGB model is based on the assumption that any desired shade of colour can be obtained by mixing the correct amounts of red, green, and blue light. The exact hues

Explain decision tree, Decision Tree A decision tree is a diagram that ...

Decision Tree A decision tree is a diagram that shows conditions and actions sequentially and therefore shows which condition is to be considered first, second and so on. It is

Algorithm, Example of worse case of time

Example of worse case of time

Whether the infix expression has balanced parenthesis or not, Using stacks,...

Using stacks, write an algorithm to determine whether the infix expression has balanced parenthesis or not Algorithm parseparens This algorithm reads a source program and

Stack, Explain in detail the algorithmic implementation of multiple stacks....

Explain in detail the algorithmic implementation of multiple stacks.

Define min-heap, Define min-heap A min-heap is a complete binary tree i...

Define min-heap A min-heap is a complete binary tree in which each element is less than or equal to its children. All the principal properties of heaps remain valid for min-hea

Explain about the abstract data type, Explain about the Abstract data type ...

Explain about the Abstract data type Abstract data type (ADT) A set of values (the carrier set) and operations on those values

Surrounding of sub division method, Surrounding of sub division method ...

Surrounding of sub division method A polygon surrounds a viewport if it completely encloses or covers the viewport. This happens if none of its sides cuts any edge of the viewp

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

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