自己写的一个全排列算法，请各位指正。

namespace permutation
{
    class Program
    {
        
        static void Main(string[] args)
        {
            for (int i = 0; i < MAX; i++)
            {
                chars[i] = (char)((int)('a') + i);
                mark[i] = 0;
            }

            Permutate();
            Console.WriteLine("Total count is: {0}", count);
        }

        private static int MAX = 8;
        private static int count = 0;
        private static char[] chars = new char[MAX];
        private static char[] output = new char[MAX];
        private static int[] mark = new int[MAX];
        private static int output_index = 0;


        private static void Permutate()
        {
            for (int i = 0; i < MAX; i++)
            {
                if (mark[i] == 0)
                {
                    output[output_index] = chars[i];
                    output_index++;

                    if (output_index == MAX)
                    {
                        count++;
                        for (int ii = 0; ii < MAX; ii++)
                            Console.Write(output[ii]);
                        Console.WriteLine();
                    }

                    mark[i] = 1;
                    Permutate();
                    mark[i] = 0;
                    output_index--;
                }
            }
        }
    }
}

运行已经没有错误，只是想知道怎么能优化一下。