public class Quicksort {
    public static int[] sort(int[] arr){

        int l = 0;
        int r = arr.length - 1;
        if(l<r) {
            int s = Math.floor((r + l) / 2)
            int arr = ArrayUtils.addAll(
                    ArrayUtils.addAll(sort(arr.copyOfRange(l, s - 1)), s), arr.copyOfRange(s + 1, r));
        }
        return arr;
    }
}