# quick sort | Java

## CodeCatch

### June 15th, 2021 12:50:47 PM

```					import java.util.Arrays;

public class QuickSortMain {

private static int array[];

public static void sort(int[] arr) {

if (arr == null || arr.length == 0) {
return;
}
array = arr;
quickSort(0, array.length-1);
}

private static void quickSort(int left, int right) {

int i = left;
int j = right;
// find pivot number, we will take it as mid
int pivot = array[left+(right-left)/2];

while (i <= j) {
/**
* In each iteration, we will increment left until we find element greater than pivot
* We will decrement right until we find element less than pivot
*/
while (array[i] < pivot) { i++; } while (array[j] > pivot) {
j--;
}
if (i <= j) {
exchange(i, j);
//move index to next position on both sides
i++;
j--;
}
}
// call quickSort() method recursively
if (left < j)
quickSort(left, j);
if (i < right)
quickSort(i, right);
}

private static void exchange(int i, int j) {
int temp = array[i];
array[i] = array[j];
array[j] = temp;
}

public static void main(String a[]){
int[] input = {33,21,45,64,55,34,11,8,3,5,1};
System.out.println("Before Sorting : ");
System.out.println(Arrays.toString(input));
sort(input);
System.out.println("==================");
System.out.println("After Sorting : ");
System.out.println(Arrays.toString(array));

}
}
```