QuickSort

void QuickSort(int *arr, int size) {
  if (size <= 1) return;
  QuickSortRecursive(arr, 0, size - 1);
}

void QuickSortRecursive(int *arr, int start, int end) {
  if (start >= end) return;

  int pivotIndex = Partition(arr, start, end);
  QuickSortRecursive(arr, start, pivotIndex - 1);
  QuickSortRecursive(arr, pivotIndex + 1, end);
}

int Partition(int *arr, int start, int end) {
  int pivot = arr[start];
  int i = start + 1;

  for (int j = start + 1; j <= end; j++) {
    if (arr[j] < pivot) {
      std::swap(arr[i], arr[j]);
      i++;
    }
  }

  std::swap(arr[start], arr[i - 1]);
  return i - 1;
}