QuickSort.java

public class QuickSort {
    public static int partition(int arr[],int low,int high){
        int pivotelm = arr[high];
        int i = low -1;
        for(int j =low;j<high;j++){
            if(arr[j] < pivotelm){
                i++;
                //swap
                int  temp =arr[i];
                arr[i] = arr[j];
                arr[j] = temp;
            }
        }
        i++;
        int temp = arr[i];
        arr[i] = arr[high];
        arr[high] = temp;
        return i;//pivot index

    }
    public static void quickSort(int arr[],int low,int high){
        if(low<high){
            int pivotidx = partition(arr,low,high);

            quickSort(arr,low,pivotidx-1);
            quickSort(arr,pivotidx+1,high);
        }
    }
    public static void main(String[] args) {
        int arr[] = {6,3,9,5,2,8};
        int n = arr.length;
        quickSort(arr,0,n-1);
        for (int i = 0;i<n;i++){
            System.out.print(arr[i]+ " ");
        }
        System.out.println();

    }
}