Heap_sort.cpp

#include <iostream>
using namespace std;
 
void heapify(int arr[], int N, int i)
{
 
    // Initialize largest as root
    int largest = i;
 
    // left = 2*i + 1
    int l = 2 * i + 1;
 
    // right = 2*i + 2
    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--) {
 
        // Move current root to end
        swap(arr[0], arr[i]);
 
        // call max heapify on the reduced heap
        heapify(arr, i, 0);
    }
}
 
{
    for (int i = 0; i < N; ++i)
        cout << arr[i] << " ";
    cout << "\n";
}
 
// Driver's code
int main()
{
    int arr[] = { 54, 13, 24, 51, 88, 107 };
    int N = sizeof(arr) / sizeof(arr[0]);
 
    // Function call
    heapSort(arr, N);
 
    cout << "Sorted array is \n";
    printArray(arr, N);
}