private void insertionSort(int low, int high){
    int i, j, temp;
    for (i = low; i < high+1; i++){
        temp = numbers[i];
        j = i;
        while (j > 0 && numbers[j - 1] > temp){
          numbers[j] = numbers[j - 1];
          j--;
        }
        numbers[j] = temp;
    }
}