1public class MergeSort {
2    public static void merge(int arr[], int l, int m, int r) {
3        int n1 = m - l + 1;
4        int n2 = r - m;
5        int L[] = new int[n1];
6        int R[] = new int[n2];
7        for (int i = 0; i < n1; ++i)
8            L[i] = arr[l + i];
9        for (int j = 0; j < n2; ++j)
10            R[j] = arr[m + 1 + j];
11        int i = 0, j = 0;
12        int k = l;
13        while (i < n1 && j < n2) {
14            if (L[i] <= R[j]) {
15                arr[k] = L[i];
16                i++;
17            } else {
18                arr[k] = R[j];
19                j++;
20            }
21            k++;
22        }
23        while (i < n1)
24            arr[k++] = L[i++];
25        while (j < n2)
26            arr[k++] = R[j++];
27    }
28
29    public static void mergeSort(int arr[], int l, int r) {
30        if (l < r) {
31            int m = (l + r) / 2;
32            mergeSort(arr, l, m);
33            mergeSort(arr, m + 1, r);
34            merge(arr, l, m, r);
35        }
36    }
37
38    public static void main(String args[]) {
39        int arr[] = {12, 11, 13, 5, 6, 7};
40        mergeSort(arr, 0, arr.length - 1);
41        for (int i = 0; i < arr.length; ++i)
42            System.out.print(arr[i] + " ");
43    }
44}
45

1#include <iostream>
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);
    }
}

int main() {
    int arr[] = {12, 11, 13, 5, 6, 7};
    int n = sizeof(arr) / sizeof(arr[0]);
    heapSort(arr, n);
    for (int i = 0; i < n; i++)
        cout << arr[i] << " ";
    return 0;
}