Complexity of quick sort, Data Structure & Algorithms

Assignment Help:

Q. What do you mean by the best case complexity of quick sort and outline why it is so. How would its worst case behaviour arise?                                                                                                 

Ans:

In the best case complexity, pivot is in the middle. To simplify the calculation, we assume that the two sub-files are both  exactly half  of the size of the original file, and although this gives a minor overestimate, this is except able because we are only interested in a Big-Oh answer.

T(n) = 2T(n/2) + cn

which yields

T(n) = cn log n + n = O(n log n)

In the worst case the pivot is the smallest element, all the time. Then i = 0 and if we ignore  T(0) = 1, which is not important, the recurrence is T(n) = T(n - 1) + cn, n > 1 which yields

1908_Quick Sort1.png


Related Discussions:- Complexity of quick sort

Present the algorithm of binary search. , B i n a ry Search Alg...

B i n a ry Search Algorithm is given as follows 1. if (low > high) 2.     return (-1) 3. mid = (low +high)/2; 4. if ( X = = a [mid]) 5.      return (mid); 6.

C++, 7. String manipulation 7.a Write a C Program using following strin...

7. String manipulation 7.a Write a C Program using following string manipulation functions a) strcpy b) strncpy c) strcmp d) strncmp e) strlen f) strcat

Algorithm for determining strongly connected components, Algorithm for dete...

Algorithm for determining strongly connected components of a Graph: Strongly Connected Components (G) where d[u] = discovery time of the vertex u throughout DFS , f[u] = f

Algorithm for linear search, Here,  m represents the unordered array of ele...

Here,  m represents the unordered array of elements n  represents number of elements in the array and el  represents the value to be searched in the list Sep 1: [Initialize]

The space - time trade off, The best algorithm to solve a given problem is ...

The best algorithm to solve a given problem is one that requires less space in memory and takes less time to complete its execution. But in practice it is not always possible to

Objectives of lists, After going through this unit, you will be able to: ...

After going through this unit, you will be able to: • define and declare Lists; • understand the terminology of Singly linked lists; • understand the terminology of Doubly

Indexed sequential file organisation, When there is requirement to access r...

When there is requirement to access records sequentially by some key value and also to access records directly by the similar key value, the collection of records may be organized

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

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

Hw7, Handout 15 COMP 264: Introduction to Computer Systems (Section 001) Sp...

Handout 15 COMP 264: Introduction to Computer Systems (Section 001) Spring 2013 R. I. Greenberg Computer Science Department Loyola University Water TowerCampus, Lewis Towers 524 82

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