// C++ program for implementation of Heap Sort
#include <iostream>
using namespace std;
// To heapify a subtree rooted with node i which is
// an index in arr[]. n is size of heap
void heapify(int arr[], int n, int i)
{
int largest = i; // Initialize largest as root
int l = 2*i + 1; // left = 2*i + 1
int r = 2*i + 2; // right = 2*i + 2
// If left child is larger than root
if (l < n && arr[l] > arr[largest])
largest = l;
// If right child is larger than largest so far
if (r < n && arr[r] > arr[largest])
largest = r;
// If largest is not root
if (largest!=i)
{
swap(arr[i], arr[largest]);
//which ever is large left or right from ROOT will be swap by ROOT
//a[i] is root,a[largest] is left or right node value.
// Recursively heapify the affected sub-tree
heapify(arr, n, largest);
}
}
// main function to build max heap
void heapSort(int arr[], int n)
{
// Build heap (rearrange array)
for (int i = n/2-1; i >= 0; i--)
{
heapify(arr, n, i);
}
// One by one extract an element from heap
for(int k=n-1;k>=0;k--)
{
// Move Root Node to end
swap(arr[0], arr[k]);
// call max heapify on the reduced heap
heapify(arr, k, 0);
}
}
/* A utility function to print array of size n */
void printArray(int arr[], int n)
{
for (int i=0; i<n; ++i)
cout << arr[i] << " ";
cout << "\n";
}
// Driver program
int main()
{
int arr[] = {50,75,60,35,45,25,95};
int n = sizeof(arr)/sizeof(arr[0]);
heapSort(arr, n);
cout << "Sorted array is \n";
printArray(arr, n);
}
