heapsort.cpp

//BISMILLAHIR RAHMANIR RAHEEM
//ALLAH IS WATCHING ME
// Shoeb Akibul Islam
// Dept of ICE, NSTU
#include<bits/stdc++.h>
using namespace std;

using ll = long long;
using pii= pair<int,int>;

const int N=200005;
ll mod= 1e9+7;
void heapify(int arr[], int N, int i)
{
    cout << "N " << N << " " << i << '\n';
    // 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 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) {
        cout << "i " << i << ' ' << largest << '\n';
        swap(arr[i], arr[largest]);

        // Recursively heapify the affected
        // sub-tree
        heapify(arr, N, largest);
    }
}

// Main function to do heap sort
void heapSort(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);
    }
}

// A utility function to print array of size n
void printArray(int arr[], int N)
{
    for (int i = 0; i < N; ++i)
        cout << arr[i] << " ";
    cout << "\n";
}

void solve(int tc)
{
    int arr[] = { 40, 10, 12, 45, 45, 40, 41, 47 };
    int N = sizeof(arr) / sizeof(arr[0]);

    // Function call
    heapSort(arr, N);

    cout << "Sorted array is \n";
    printArray(arr, N);
}



signed main()
{
    int test_case=1;
//    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
//    cin >> test_case;
    for(int i = 1; i <= test_case ; i++)
        solve(i);
    return 0;
}



///  Alhamdulillah...