public static void sort(int arr[]) {
    int start = 0;
    int length = arr.length;
    while (start < arr.length / 2) {
        int min = arr[start], mini = start;
        int max = arr[start], maxi = start;
        for (int j = start; j < length; j++) {
            if (min > arr[j]) {
                min = arr[j];
                mini = j;
            }
            if (max < arr[j]) {
                max = arr[j];
                maxi = j;
            }
        }
        if (arr[start] != min) {
            arr[mini] = arr[start];
            arr[start] = min;
            maxi++;
        }
        if (arr[length - 1] != max) {
            arr[maxi] = arr[length - 1];
            arr[length - 1] = max;
        }
        start++;
        length--;
    }
}