heapSort.cpp

//RISHABH JHA
//git-rishabh-jha
//Program for Heap Sort

#include <bits/stdc++.h>

using namespace std;
void heapify(int arr[], int n, int i)
{
	int largest = i;
	int l = 2*i + 1;
	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--) {
		swap(arr[0], arr[i]);

		heapify(arr, i, 0);
	}
}

void printArray(int arr[], int n) {
	for (int i=0; i<n; ++i){
		cout << arr[i] << " ";
  }
	cout << "\n";
}

int main()
{
  int n;
  cout<<"\n\n\t\tHEAP SORT\n\nENTER THE NUMBER OF ELEMENTS IN THE ARRAY: ";
  cin>>n;
  int arr[n];
  cout<<"\nENTER THE ELEMENTS OF THE ARRAY: ";
  for(int i=0;i<n;i++){
    cin>>arr[i];
  }
	heapSort(arr, n);

	cout << "\n\t SORTED ARRAY: ";
	printArray(arr, n);
}