Quick_Sort_Array.java

public class Quick_Sort_Array {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int[] arr = { 5, 7, 2, 3, 8, 9, 1, 4 };
        sort(arr, 0, arr.length - 1);
        for (int i = 0; i < arr.length; i++) {
            System.out.print(arr[i] + " ");
        }

    }

    public static void sort(int[] arr, int si, int ei) {
        if (si > ei) {
            return;
        }
        int pi = partition(arr, si, ei);
        sort(arr, si, pi - 1);
        sort(arr, pi + 1, ei);

    }

    public static int partition(int[] arr, int si, int ei) {

        int item = arr[ei];
        int pi = si;

        for (int i = si; i < ei; i++) {
            if (arr[i] < item) {
                int ii = arr[i];
                arr[i] = arr[pi];
                arr[pi] = ii;
                pi++;

            }
        }

        int ii = arr[ei];
        arr[ei] = arr[pi];
        arr[pi] = ii;
        return pi;

    }

}