Heap sort.cpp

#include <iostream>
using namespace std;
  
void heapify(int arr[], int n, int i)
{
    int largest = i; 
    int l = 2 * i + 1; 
    int r = 2 * i + 2; 
  
   
    if (l < n && arr[l] > arr[largest])
        largest = l;
  
   
    if (r < n && arr[r] > arr[largest])
        largest = r;
  
    
    if (largest != i) {
        swap(arr[i], 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 printArray(int arr[], int n)
{
    for (int i = 0; i < n; ++i)
        cout << arr[i] << " ";
    cout << "\n";
}
  

int main()
{
    int arr[] = { 12, 11, 13, 5, 6, 7 };
    int n = sizeof(arr) / sizeof(arr[0]);
  
    heapSort(arr, n);
  
    cout << "Sorted array is \n";
    printArray(arr, n);
}