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

Explain circular queues, Circular Queues:- A more efficient queue repre...

Circular Queues:- A more efficient queue representation is get by regarding the array Q(1:n) as circular. It becomes more convenient to declare the array as Q(O: n-1), when  re

Determine the warnock algorithm, Warnock's Algorithm A divide and conqu...

Warnock's Algorithm A divide and conquer algorithm Warnock (PolyList PL, ViewPort VP) If (PL simple in VP) then Draw PL in VP, else Split VP vertically and horiz

Advanced data structures, In this unit, the following four advanced data st...

In this unit, the following four advanced data structures have been practically emphasized. These may be considered as alternative to a height balanced tree, i.e., AVL tree.

Operating system, discuss the operating system under the following: MONOLIT...

discuss the operating system under the following: MONOLITHIC SYSTEM,LAYER SYSTEM AND VIRTUAL MACHINES

Linked lists - implementation, The Linked list is a chain of structures whe...

The Linked list is a chain of structures wherein each structure contains data in addition to pointer, which stores the address (link) of the next logical structure in the list.

Determine about the push operation, Determine about the push operation ...

Determine about the push operation A Container may or may not be accessible by keys, so it can't make assumptions about element retrieval methods (for example, it cannot have a

Define tree ?, A tree is a non-empty set one component of which is designat...

A tree is a non-empty set one component of which is designated the root of the tree while the remaining components are partitioned into non-empty groups each of which is a subtree

The complexity of searching an element, The complexity of searching an elem...

The complexity of searching an element from a set of n elements using Binary search algorithm is   O(log n)

Deletion algorithm for dequeue, Deletion Algorithm for dequeue Step 1:...

Deletion Algorithm for dequeue Step 1: [check for underflow]   If front = 0 and rear = 0   Output "underflow" and return Step 2: [delete element at front end]   If front

Explain state space tree, Explain State Space Tree If it is convenient ...

Explain State Space Tree If it is convenient to execute backtracking by constructing a tree of choices being made, the tree is known as a state space tree. Its root indicates a

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