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  1. #include <iostream>
  2. #include <vector>
  3. using namespace std;
  4.  
  5. template <typename T,typename Comparator = std::less<int>>
  6. void mergeSort(T* arr, size_t start, size_t end, Comparator cmp = Comparator())
  7. {
  8.     if (end - start < 2)
  9.         return;
  10.     if (end - start == 2)
  11.     {
  12.         if (cmp(arr[start + 1], arr[start]))
  13.             swap(arr[start], arr[start + 1]);
  14.         return;
  15.     }
  16.     mergeSort<T>(arr, start, start + (end - start) / 2, cmp);
  17.     mergeSort<T>(arr, start + (end - start) / 2, end, cmp);
  18.     size_t auxSize = end - start;
  19.     T* aux = new T[auxSize];
  20.     size_t b1 = start;
  21.     size_t e1 = start + (end - start) / 2;
  22.     size_t b2 = e1;
  23.     size_t auxCurrentIndex = 0;
  24.     while (auxCurrentIndex < end - start)
  25.     {
  26.         if (b1 >= e1 || (b2 < end && cmp(arr[b2], arr[b1])))
  27.         {
  28.             aux[auxCurrentIndex] = arr[b2];
  29.             ++b2;
  30.         }
  31.         else
  32.         {
  33.             aux[auxCurrentIndex] = arr[b1];
  34.             ++b1;
  35.         }
  36.         auxCurrentIndex++;
  37.     }
  38.     for (size_t i = start; i < end; ++i)
  39.         arr[i] = aux[i - start];
  40. }
  41.  
  42. int main()
  43. {
  44.     int a[10] = {5, 4, 0, 9, 6, -10, 10, 9, 3, -2};
  45.     mergeSort<int>(a, 0, 10);
  46.     for (std::size_t i = 0; i < 10; i++){
  47.         std::cout << a[i] << ' ';
  48.     }
  49.     cout << "\n\n";
  50.     mergeSort<int,std::greater<int>>(a, 0, 10);
  51.     for (std::size_t i = 0; i < 10; i++){
  52.         std::cout << a[i] << ' ';
  53.     }
  54. }
  55.  
Success #stdin #stdout 0s 4352KB
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stdin
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Standard input is empty
stdout
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-10 -2 0 3 4 5 6 9 9 10 

10 9 9 6 5 4 3 0 -2 -10
https://ideone.com/jAFQNw
language:
C++14 (gcc 8.3)
created:
3 years ago
visibility:
public

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