QuickSort.java

package com.interview.sort;

public class QuickSort {

    private void swap(int A[],int i,int j)
    {
        int temp = A[i];
        A[i] = A[j];
        A[j] = temp;
    }
    private int split(int A[],int low,int high)
    {
        int pivot = low;
        int i = low +1;
        int j = high;
        while(i<j)
        {
            while(i<=j && A[pivot]>=A[i])
            {
                i++;
            }
            while(j>=i && A[pivot]<A[j])
            {
                j--;
            }
            if(i < j && A[i]>A[j])
            {
                swap(A,i++,j--);
            }
        }
        if(A[pivot] > A[j]){
            swap(A,j,pivot);
        }
        return j;
    }

    private int split1(int A[],int low,int high){
        
        int pivot = low;
        int i = low+1;
        int j = high;
        while(i <= j){
            
            if(A[i] <= A[pivot]){
                i++;
                continue;
            }
            if(A[j] > A[pivot]){
                j--;
                continue;
            }
            swap(A,i++,j--);
        }
        if(A[pivot] > A[j]){
            swap(A,pivot,j);
            return j;
        }
        return pivot;
        
    }

    public void sort(int A[],int low,int high)
    {
        if(low>=high)
        {
            return;
        }
        int pos = split1(A,low,high);
        sort(A,low,pos-1);
        sort(A,pos+1,high);
    }   
    
    private void printArray(int arr[]){
        for(int a : arr){
            System.out.println(a);
        }
    }
    public static void main(String args[]){
        QuickSort qs = new QuickSort();
        int A[] = {11,19,0,-1,5,6,16,-3,6,0,14,18,7,21,18,-6,-8};
//      int A[] = {11,9,0,4,6,-1,13};
        qs.sort(A, 0, A.length-1);
        qs.printArray(A);
        
    }
}