U64 qsort_partition_F64(SortPair_F64 *pairs, U64 size, U64 low, U64 high) {
  F64 pivot = pairs[high].value;
  U64 i = low - 1;

  SortPair_F64 temp = {0};
  for (U64 j = low; j < high; j++) {
    if (pairs[j].value <= pivot) {
      i += 1;
      temp = pairs[i];
      pairs[i] = pairs[j];
      pairs[j] = temp;
    }
  }

  U64 final_pivot_pos = i + 1;
  temp = pairs[final_pivot_pos];
  pairs[final_pivot_pos] = pairs[high];
  pairs[high] = temp;

  return final_pivot_pos;
}

function void qsort_F64(SortPair_F64 *pairs, U64 size, U64 low, U64 high) {
  if (low < high) {
    U64 pivot_index = qsort_partition_F64(pairs, size, low, high);
    qsort_F64(pairs, size, low, pivot_index - 1);
    qsort_F64(pairs, size, pivot_index + 1, high);
  }
}

function void sort_and_get_indices_F64(F64 *array, U64 *indices, U64 size) {
  SortPair_F64 *pairs = malloc(size * sizeof(SortPair_F64));
  for (U64 i = 0; i < size; i++) {
    pairs[i].value = array[i];
    pairs[i].original_index = i;
  }

  qsort_F64(pairs, size, 0, size - 1);

  for (U32 i = 0; i < size; i++) {
    array[i] = pairs[i].value;
    indices[i] = pairs[i].original_index;
  }

  free(pairs);
}

function void sort_by_indices_F64(F64 *array, U64 *indices, U64 size) {

  F64 *temp = malloc(size * sizeof(F64));
  for (U64 i = 0; i < size; i++) {
    U64 original_index = indices[i];
    temp[i] = array[original_index];
  }
  for (U64 i = 0; i < size; i++) {
    array[i] = temp[i];
  }
  free(temp);
}