如何修复c#中合并排序的实现

using System;

class MergeSort
{
    static void Merge(int[] arr, int left, int mid, int right)
    {
        int n1 = mid - left + 1;
        int n2 = right - mid;

        int[] L = new int[n1];
        int[] R = new int[n2];

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

        for (int j = 0; j < n2; ++j)
            R[j] = arr[mid + 1 + j];

        int p = 0, q = 0;
        int k = left;

        while (p < n1 && q < n2)
        {
            if (L[p] <= R[q])
            {
                arr[k] = L[p];
                p++;
            }
            else
            {
                arr[k] = R[q];
                q++;
            }
            k++;
        }

        while (p < n1)
        {
            arr[k] = L[p];
            p++;
            k++;
        }

        while (q < n2)
        {
            arr[k] = R[q];
            q++;
            k++;
        }
    }

    static void MergeSortFunc(int[] arr, int left, int right)
    {
        if (left < right)
        {
            int mid = (left + right) / 2;

            MergeSortFunc(arr, left, mid);
            MergeSortFunc(arr, mid + 1, right);

            Merge(arr, left, mid, right);
        }
    }

    static void Main()
    {
        int[] arr = { 12, 11, 13, 5, 6, 7 };
        int n = arr.Length;

        Console.WriteLine("Original array:");
        PrintArray(arr);

        MergeSortFunc(arr, 0, n - 1);

        Console.WriteLine("\nSorted array:");
        PrintArray(arr);
    }

    static void PrintArray(int[] arr)
    {
        int n = arr.Length;
        for (int i = 0; i < n; ++i)
            Console.Write(arr[i] + " ");
        Console.WriteLine();
    }
}