Data-Structures-and-Algorithms/intro_sort.cpp at master · patelpreet422/Data-Structures-and-Algorithms · GitHub

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class Solution {
public:
  void insertion_sort(vector<int> &v, int l, int h) {
    for (int i = l + 1; i <= h; ++i) {
      int j = i - 1;
      while (j >= 0 and v[j] > v[j + 1]) {
        swap(v[j], v[j + 1]);
        --j;
      }
    }
  }

  void heap_sort(vector<int> &v, int l, int h) {
    make_heap(begin(v) + l, begin(v) + h + 1);
    sort_heap(begin(v) + l, begin(v) + h + 1);
  }

  int partition(vector<int> &v, int l, int h) {
    swap(v[l + (rand() % (h - l + 1))], v[h]);
    int i = l - 1;
    for (int j = l; j <= h; ++j) {
      if (v[j] <= v[h]) {
        swap(v[++i], v[j]);
      }
    }
    return i;
  }

  void intro_sort(vector<int> &v, int max_depth, int l, int h) {
    if (l >= h)
      return;
    if (h - l + 1 <= 16) {
      insertion_sort(v, l, h);
    } else if (max_depth == 0) {
      heap_sort(v, l, h);
    } else {
      int p = partition(v, l, h);
      intro_sort(v, max_depth - 1, l, p - 1);
      intro_sort(v, max_depth - 1, p + 1, h);
    }
  }

  void quick_sort(vector<int> &v, int l, int h) {
    if (l >= h)
      return;
    int p = partition(v, l, h);
    quick_sort(v, l, p - 1);
    quick_sort(v, p + 1, h);
  }

  vector<int> sortArray(vector<int> &nums) {
    intro_sort(nums, 32, 0, nums.size() - 1);
    return nums;
  }
};