public static void Merge(int[] arr,int p,int q,int r ) 
{
    int n1 = q-p;
    int n2 = r-q;
    int[] L=new int[n1];
    int[] R = new int[r-n2];

    for (int i = 0; i < n1; i++)
        L[i] = arr[i];

    foreach (int x in L)
        Console.WriteLine(x);

    for (int i = 0; i < n2; i++)
        R[i] = arr[q+i];

    Console.WriteLine("New part");

    foreach (int x in R)
        Console.WriteLine(x);

    int k=0, d=0;

    for (int i = p; i < r; i++)
    {
        if (L[k] <= R[k])
        {
            arr[i] = L[k];
            k++;
        }
        else
        {
            arr[i] = R[d];
            d++;
        }
    }
}

上面的代码显示exception(index out of bound when I call from main() method using Merge(arr,0,0,12)。其中arr是长度为12的int数组。