using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        sortAndPrint(new int[0]);

        sortAndPrint(new int[]{43});

        sortAndPrint(new int[]{31,7});

        sortAndPrint(new int[] { 2,55,44});

        sortAndPrint(new int[]{8, 4, 2, 4, 6, 3, 22, 44, 33, 1, 55, 86,34,28,64});

    }

    private static void sortAndPrint(int[] a){

        MergeSort(a);

        for(int i = 0 ; i < a.Length; i++)

        {

            Console.Write(a[i] + " ");

        }

        Console.WriteLine("");

    }

    public static void MergeSort(int[] a){

        if(a.Length <= 1 )

            return ;

         MergeSortHelper(a, 0, a.Length-1);

    }

    private static void MergeSortHelper(int[] a, int s, int e){

        if(s >= e)

            return ;

        int m = (s+e)/2;

        MergeSortHelper(a, s, m);

        MergeSortHelper(a, m+1, e);

        int[] temp = new int[e-s+1];

        int k = 0 ;

        int i = s;

        int j = m+1;

        while(i <= m && j <= e)

            if(a[i] < a[j]){

                temp[k++] = a[i++];

            }

            else{

                temp[k++] = a[j++];

            }

        while(i <= m)

            temp[k++] = a[i++];

        while(j <= e)

            temp[k++] = a[j++];

        i = s;

        for(k = 0 ; k < temp.Length; k++, i++){

           a[i] = temp[k];

        }

    }

}

​

​

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