hacktoberfest2k20_2/HeapSort.cpp at master · Lokender10/hacktoberfest2k20_2 · GitHub

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#include <iostream>
using namespace std;


void heapify(int arr[], int n, int root)
{
   int largest = root;
   int l = 2*root + 1;
   int r = 2*root + 2;

   if (l < n && arr[l] > arr[largest])
   largest = l;


   if (r < n && arr[r] > arr[largest])
   largest = r;


   if (largest != root)
      {
      swap(arr[root], arr[largest]);

      heapify(arr, n, largest);
      }
}

void heapSort(int arr[], int n)
{

   for (int i = n / 2 - 1; i >= 0; i--)
   heapify(arr, n, i);


   for (int i=n-1; i>=0; i--)
   {
      swap(arr[0], arr[i]);

      heapify(arr, i, 0);
   }
}

void displayArray(int arr[], int n)
{
   for (int i=0; i<n; ++i)
   cout << arr[i] << " ";
   cout << "\n";
}

int main()
{
   int heap_arr[] = {4,17,3,12,9,6};
   int n = sizeof(heap_arr)/sizeof(heap_arr[0]);
   cout<<"Input array"<<endl;
   displayArray(heap_arr,n);

   heapSort(heap_arr, n);

   cout << "Sorted array"<<endl;
   displayArray(heap_arr, n);
}