maxHeapsort.cpp

#include <iostream>
#include<vector>
using namespace std;

void heapify(vector<int> &arr, int n, int i)
{
    int largest = i;
    int l = 2*i + 1;
    int r = 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]);
 
        // recursively heapify the affected sub-tree
        heapify(arr, n, largest);
    }
}

void heapSort(vector<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 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);
    }
}
 
/* function to print array of size n */
void printArray(vector<int> &arr, int n)
{
    for (int i = 0; i < n; i++)
    {
        cout << arr[i] << " ";
    }
    cout << "\n";
}
 

int main()
{
 	vector<int> v;	
	int n;
	cout<<"Enter Size Of Array:";
	cin>>n;
	for(int i=0;i<n;i++)
	{
		int x;
		cin>>x;
		v.push_back(x);
	}
    heapSort(v, n);
 
    cout << "Sorted array is \n";
    printArray(v, n);
}