1function mergeSort(arr) {
2    if (arr.length > 1) {
3        const mid = Math.floor(arr.length / 2);
4        const L = arr.slice(0, mid);
5        const R = arr.slice(mid);
6
7        mergeSort(L);
8        mergeSort(R);
9
10        let i = 0, j = 0, k = 0;
11        while (i < L.length && j < R.length) {
12            if (L[i] < R[j]) {
13                arr[k++] = L[i++];
14            } else {
15                arr[k++] = R[j++];
16            }
17        }
18
19        while (i < L.length) arr[k++] = L[i++];
20        while (j < R.length) arr[k++] = R[j++];
21    }
22    return arr;
23}
24
25const arr = [12, 11, 13, 5, 6, 7];
26console.log(mergeSort(arr));
27

1using System;

class HeapSort {
    public 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) {
            int swap = arr[i];
            arr[i] = arr[largest];
            arr[largest] = swap;
            Heapify(arr, n, largest);
        }
    }

    public void Sort(int[] arr) {
        int n = arr.Length;

        for (int i = n / 2 - 1; i >= 0; i--)
            Heapify(arr, n, i);

        for (int i = n - 1; i >= 0; i--) {
            int temp = arr[0];
            arr[0] = arr[i];
            arr[i] = temp;
            Heapify(arr, i, 0);
        }
    }

    static void Main() {
        int[] arr = {12, 11, 13, 5, 6, 7};
        HeapSort hs = new HeapSort();
        hs.Sort(arr);
        Console.WriteLine(string.Join(" ", arr));
    }
}