Quick Sort in Data Structures
Prof. Neeraj Bhargava
Kapil Chauhan
Department of Computer Science
School of Engineering & Systems Sciences
MDS University, Ajmer
Introduction
 Quick sort is a fast sorting algorithm used to sort a list
of elements.
 The quick sort algorithm attempts to separate the list
of elements into two parts and then sort each part
recursively.
Cont..
 That means it use divide and conquer strategy.
 In quick sort, the partition of the list is performed
based on the element called pivot.
Cont…
 Here pivot element is one of the elements in the list.
 The list is divided into two partitions such that "all
elements to the left of pivot are smaller than the
pivot and all elements to the right of pivot are
greater than or equal to the pivot".
Cont..
 It is also called partition-exchange sort. This
algorithm divides the list into three main parts:
 Elements less than the Pivot element
 Pivot element(Central element)
 Elements greater than the pivot element
Example
Algorithm
 Step 1 − Choose the highest index value has pivot
 Step 2 − Take two variables to point left and right of the list
excluding pivot
 Step 3 − left points to the low index
 Step 4 − right points to the high
 Step 5 − while value at left is less than pivot move right
Step 6 − while value at right is greater than pivot move left
 Step 7 − if both step 5 and step 6 does not match swap left
and right
 Step 8 − if left ≥ right, the point where they met is new
pivot
Assignment
 Explain Quick Sort in data structure with suitable
example and discuss basic operation.

Quick sort data structures

  • 1.
    Quick Sort inData Structures Prof. Neeraj Bhargava Kapil Chauhan Department of Computer Science School of Engineering & Systems Sciences MDS University, Ajmer
  • 2.
    Introduction  Quick sortis a fast sorting algorithm used to sort a list of elements.  The quick sort algorithm attempts to separate the list of elements into two parts and then sort each part recursively.
  • 3.
    Cont..  That meansit use divide and conquer strategy.  In quick sort, the partition of the list is performed based on the element called pivot.
  • 4.
    Cont…  Here pivotelement is one of the elements in the list.  The list is divided into two partitions such that "all elements to the left of pivot are smaller than the pivot and all elements to the right of pivot are greater than or equal to the pivot".
  • 5.
    Cont..  It isalso called partition-exchange sort. This algorithm divides the list into three main parts:  Elements less than the Pivot element  Pivot element(Central element)  Elements greater than the pivot element
  • 6.
  • 7.
    Algorithm  Step 1− Choose the highest index value has pivot  Step 2 − Take two variables to point left and right of the list excluding pivot  Step 3 − left points to the low index  Step 4 − right points to the high  Step 5 − while value at left is less than pivot move right Step 6 − while value at right is greater than pivot move left  Step 7 − if both step 5 and step 6 does not match swap left and right  Step 8 − if left ≥ right, the point where they met is new pivot
  • 8.
    Assignment  Explain QuickSort in data structure with suitable example and discuss basic operation.