docs: public static double select(final double[] arr, int lo, int hi, final int pivot) {
      while (hi > lo) {
        final int j = partition(arr, lo, hi);
        if (j == pivot) {
          return arr[pivot];
        }
        if (j > pivot) {
          hi = j - 1;
        }
        else {
          lo = j + 1;
        }
      }
      return arr[pivot];
    }