Cannot implement quick sort algorithm using pivot as middle element.how do I solve it?

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1.00/5 (3 votes)

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Java

public static int partition(int array[],int start,int end)
`    {
        int pivot_index=(start+end)/2;
        int pivot=array[pivot_index];
        int i=start;
        int j=end;
        while(i<j)
 {
="" while(array[i]<="pivot)
" i++;
="" }
="" while(array[j]="">pivot)
            {
                j--;
            }
           
            if(i<j)
 {="" 
="" swap(array,i,j);
="" }
="" return="" j;
="" }

<b="">

What I have tried:

What I have tried:

I want to take pivot as the middle element. Output is not coming. Infinite loop is happening for certain test cases.For example array={3,1,2,2,2}.Please tell the modifications required in the code to get the necessary output.

Posted 2-May-23 9:32am

Shuvradip Sarma

Updated 2-May-23 10:12am

Patrice T

v2

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Comments

Patrice T 2-May-23 16:14pm

Your code was corruoted.
Please paste again

Mike Hankey 2-May-23 18:09pm

What do you get when you run it through the debugger?

Shuvradip Sarma 3-May-23 9:28am

output - 3,1,2,2,2

the full code is-

import java.util.*;
class quick_sort_algo
{
public static void main(String args[])
{
Scanner sc=new Scanner(System.in);
System.out.println("enter the length of the array");
int n=sc.nextInt();
int array[]=new int[n];
System.out.println("enter element in the array");
for(int i=0;i<array.length;i++)
{
="" array[i]="sc.nextInt();
" }
="" system.out.println("array="" before="" sorting");
="" for(int="" i="0;i<array.length;i++)
" system.out.print(array[i]+"="" ");
="" system.out.println();
="" int="" start="0;
" end="array.length-1;
" quick_sort_algo="" call="new" quick_sort_algo();
="" call.quick_sort(array,start,end);
="" after="" public="" static="" void="" swap(int="" array[],int="" i,int="" j)
="" t="array[i];
" array[j]="t;
" partition(int="" start,int="" end)
="" pivot_index="(start+end)/2;
" pivot="array[pivot_index];
" j="end;
" while(i<j)
="" while(array[i]<pivot)
="" i++;
="" while(="">pivot)
{
j--;
}
if(i

Richard Deeming 3-May-23 10:01am

Still not the full code, and still corrupt.

Don't try to post code in the comments; instead, click the green "Improve question" link and update your question.

Dave Kreskowiak 2-May-23 21:24pm

If that's all the code you have, and it was corrupted when you pasted it into your question, that's nowhere near the code required for quicksort.

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