quick sort

import java.util.Arrays;

public class Main {
    public static void main(String[] args) {

        int[] arr = {5,4,3,2,1};

        quickSort(arr,0,arr.length-1);
        System.out.println(Arrays.toString(arr));

    }

    private static void quickSort(int[] arr, int low, int high) {
        if(low>=high)return;

        int start=low;
        int end=high;
        int mid=start+(end-start)/2;
        int pivot=arr[mid];
        while(start<=end){
            while(arr[start]<pivot){
                start++;
            }
            while(arr[end]>pivot){
                end--;
            }
            if(start<=end){
                swap(arr,start,end);
                start++;
                end--;
            }
        }
        quickSort(arr,low,end);
        quickSort(arr,start,high);

    }
private static void dualPivotQuickSort(int[] arr,int low,int high){
        if(low>=high) return;

        if(arr[low]>arr[high]){
            swap(arr,low,high);
        }
        int pivot1=arr[low];
        int pivot2=arr[high];

        int index=low+1;
        int start=low+1;
        int end=high-1;
        while(index<=end){
            if(arr[index]<pivot1){
                swap(arr,index,start);
                start++;
            }else if(arr[index]>pivot2){
                swap(arr,index,end);
                end--;
                index--;
            }
            index++;
        }
        start--;
        end++;
        swap(arr,low,start);
        swap(arr,high,end);

        //for left of pivot1
       dualPivotQuickSort(arr,low,start-1);
       //for between the pivots
       if(arr[start]!=arr[end]){
           dualPivotQuickSort(arr,start,end-1);
       }
        //for right of pivot2
        dualPivotQuickSort(arr,end+1,high);

    }

    private static void swap(int[] arr,int i,int j){
        if(i!=j) {
            int temp = arr[i];
            arr[i] = arr[j];
            arr[j] = temp;
        }
    }

}