HeapSort.cpp

#include <iostream>
using namespace std;

void Heapify(int arr[], int n, int i)
{
    int largest = i;
    int left = 2 * i + 1;
    int right = 2 * i + 2;
    if (left < n && arr[left] > arr[largest])
        largest = left;
    if (right < n && arr[right] > arr[largest])
        largest = right;
    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);
    }
}

int main()
{
    int arr[] = {5, 4, 3, 2, 1};
    int n = sizeof(arr) / sizeof(arr[0]);
    HeapSort(arr, n);
    for (int i = 0; i < n; i++)
        cout << arr[i] << " ";
    return 0;
}