public static void main(String[] args) {

int[] arr = { 10, 20, 30, 40, 10 };

quickSort(arr, 0, arr.length - 1);

for (int val : arr) {

System.out.print(val + " ");

}

}

public static void quickSort(int[] arr, int lo, int hi) {

if (lo >= hi) {

return;

}

int mid = (lo + hi) / 2;

int pivot = arr[mid];

// partitioning

int left = lo;

int right = hi;

while (left <= right) {

// left problem

while (arr[left] < pivot) {

left++;

}

// right problem

while (arr[right] > pivot) {

right--;

}

// problem solve

if (left <= right) {

int temp = arr[left];

arr[left] = arr[right];

arr[right] = temp;

left++;

right--;

}

}

// partitioning completed

// smaller parts sort

quickSort(arr, lo, right);

quickSort(arr, left, hi);

}