Java Program to Implement Quick Sort with Given Complexity Constraint

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This is a java program to perform quick sort with complexity constraint of time less than n^2.

Here is the source code of the Java Program to Implement Quick Sort with Given Complexity Constraint. The Java program is successfully compiled and run on a Windows system. The program output is also shown below.

  1.  
  2. package com.sanfoundry.combinatorial;
  3.  
  4. import java.util.Random;
  5.  
  6. public class QuickSortComplexityConstraint
  7. {
  8.     public static int N = 20;
  9.     public static int[] sequence = new int[N];
  10.  
  11.     public static void QuickSort(int left, int right)
  12.     {
  13.         if (right - left <= 0)
  14.             return;
  15.         else
  16.         {
  17.             Random rand = new Random();
  18.             int pivotIndex = left + rand.nextInt(right - left + 1);
  19.             swap(pivotIndex, right);
  20.             int pivot = sequence[right];
  21.             int partition = partitionIt(left, right, pivot);
  22.             QuickSort(left, partition - 1);
  23.             QuickSort(partition + 1, right);
  24.         }
  25.     }
  26.  
  27.     public static int partitionIt(int left, int right, long pivot)
  28.     {
  29.         int leftPtr = left - 1;
  30.         int rightPtr = right;
  31.         while (true)
  32.         {
  33.             while (sequence[++leftPtr] < pivot)
  34.                 ;
  35.             while (rightPtr > 0 && sequence[--rightPtr] > pivot)
  36.                 ;
  37.             if (leftPtr >= rightPtr)
  38.                 break;
  39.             else
  40.                 swap(leftPtr, rightPtr);
  41.         }
  42.         swap(leftPtr, right);
  43.         return leftPtr;
  44.     }
  45.  
  46.     public static void swap(int dex1, int dex2)
  47.     {
  48.         int temp = sequence[dex1];
  49.         sequence[dex1] = sequence[dex2];
  50.         sequence[dex2] = temp;
  51.     }
  52.  
  53.     static void printSequence(int[] sorted_sequence)
  54.     {
  55.         for (int i = 0; i < sorted_sequence.length; i++)
  56.             System.out.print(sorted_sequence[i] + " ");
  57.     }
  58.  
  59.     public static void main(String args[])
  60.     {
  61.         System.out
  62.                 .println("Sorting of randomly generated numbers using QUICK SORT with complexity less than n^2");
  63.         Random random = new Random();
  64.         for (int i = 0; i < N; i++)
  65.             sequence[i] = Math.abs(random.nextInt(100));
  66.         System.out.println("\nOriginal Sequence: ");
  67.         printSequence(sequence);
  68.         System.out.println("\nSorted Sequence: ");
  69.         QuickSort(0, N - 1);
  70.         printSequence(sequence);
  71.     }
  72. }

Output:

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$ javac QuickSortComplexityConstraint.java
$ java QuickSortComplexityConstraint
 
Sorting of randomly generated numbers using QUICK SORT with complexity less than n^2
 
Original Sequence: 
29 19 67 48 23 99 72 40 23 93 0 79 70 87 43 24 56 67 51 71 
Sorted Sequence: 
0 19 23 23 24 29 40 43 48 51 56 67 67 70 71 72 79 87 93 99

Sanfoundry Global Education & Learning Series – 1000 Java Programs.

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage, Advanced C Programming, SAN Storage Technologies, SCSI Internals & Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him @ LinkedIn | Youtube | Instagram | Facebook | Twitter