ティムソート

#include <bits/stdc++.h>
using namespace std;
const int RUN = 32;

void insertionSort(int arr[], int left, int right) {
  for (int i = left + 1; i <= right; i++) {
    int temp = arr[i];
    int j = i - 1;
    while (j >= left && arr[j] > temp) {
      arr[j + 1] = arr[j];
      j--;
    }
    arr[j + 1] = temp;
  }
}

void merge(int arr[], int beg, int mid, int end) {
  int output[end - beg + 1];
  int i = beg, j = mid + 1, k = 0;
  // add smaller of both elements to the output
  while (i <= mid && j <= end) {
    if (arr[i] <= arr[j]) {
      output[k] = arr[i];
      k += 1;
      i += 1;
    } else {
      output[k] = arr[j];
      k += 1;
      j += 1;
    }
  }
  // remaining elements from first array
  while (i <= mid) {
    output[k] = arr[i];
    k += 1;
    i += 1;
  }
  // remaining elements from the second array
  while (j <= end) {
    output[k] = arr[j];
    k += 1;
    j += 1;
  }
  // copy output to the original array
  for (i = beg; i <= end; i += 1) {
    arr[i] = output[i - beg];
  }
}
void timSort(int arr[], int n) {
  for (int i = 0; i < n; i += RUN)
    insertionSort(arr, i, min((i + 31), (n - 1)));

  for (int size = RUN; size < n; size = 2 * size) {
    for (int left = 0; left < n; left += 2 * size) {
      int mid = left + size - 1;
      int right = min((left + 2 * size - 1), (n - 1));

      merge(arr, left, mid, right);
    }
  }
}

int main() {
  int n = 6;
  int arr[6] = {5, 3, 4, 2, 1, 6};
  cout << "Input array: ";
  for (int i = 0; i < n; i++) {
    cout << arr[i] << " ";
  }
  cout << "\n";
  timSort(arr, n);  // Sort elements in ascending order
  cout << "Output array: ";
  for (int i = 0; i < n; i++) {
    cout << arr[i] << " ";
  }
  cout << "\n";
}