heapsort.cpp

#include<iostream>
using namespace std;
void heapify(int a[],int n,int i)
{
    int largest=i;
    int l=2*i+1;
    int r=2*i+2;
    if(l<n && a[l]>a[largest])
    {
        largest=l;
    }
    if(r<n && a[r]>a[largest])
    {
        largest=r;
    }
    if(largest!=i)
    {
        swap(a[i],a[largest]);
        heapify(a,n,largest);
    }
}
void heapsort(int a[],int n)
{
    for(int i=n/2-1;i>=0;i--)
    {
        heapify(a,n,i);
    }
    for(int i=n-1;i>=0;i--)
    {
        swap(a[0],a[i]);
        heapify(a,i,0);
    }
}
int main()
{
    int n,i;
    cout<<"enter no of elements:";
    cin>>n;
    int a[n];
    cout<<"enter elements:";
    for(i=0;i<n;i++)
    {
        cin>>a[i];
    }
    heapsort(a,n);
    cout<<"sorted array is:";
    for(i=0;i<n;i++)
    {
        cout<<a[i]<<" ";
    }
    return 0;
}