C# -算法：最长公共子串

namespace 最长公共子串
{
    class Program
    {
        static void Main(string[] args)
        {
            string a = "efsdsfdabcdefgaabcdefgaabcdefgefg";
            string b = "efsdfdabcdeffzabcdefg";

            char[] arr = a.ToCharArray();
            char[] brr = b.ToCharArray();

            int len_a = a.Length;
            int len_b = b.Length;

            int[,] distance = InitArray(len_a, len_b, arr, brr);

            WriteArray(len_a,len_b, arr, brr, distance);

            Console.ReadLine();
        }

        private static int[,] InitArray(int len_a, int len_b, char[] arr, char[] brr)
        {
            var nums = new int[len_a + 1, len_b + 1];
            for (int i = 1; i <= len_a; i++)
            {
                for (int j = 1; j <= len_b; j++)
                {
                    if (arr[i - 1] == brr[j - 1]) nums[i, j] = nums[i - 1, j - 1] + 1;
                    else nums[i, j] = Max(nums[i - 1, j], nums[i, j - 1]);//注释这句，所求为连续的最长子串，不注释这句，所求为不连续的最长子串
                }
            }
            return nums;
        }

        private static int Max(int p1, int p2)
        {
            int max = p1;
            if (max < p2) max = p2;
            return max;
        }

        private static int Max(int p1, int p2, int p3)
        {
            int max = p1;
            if (max < p2) max = p2;
            if (max < p3) max = p3;
            return max;
        }
        private static void WriteArray(int len_a,int len_b ,char[] arr, char[] brr, int[,] distance)
        {
            for (int j = 0; j <= len_b; j++)
            {
                if (j > 0)
                    Console.Write(brr[j - 1] + "  ");
                else Console.Write("      ");
            }
            Console.WriteLine();
            for (int i = 0; i <= len_a; i++)
            {
                if (i > 0)
                    Console.Write(arr[i - 1] + " ");
                else Console.Write("  ");
                for (int j = 0; j <= len_b; j++)
                {
                    Console.Write(ToString(distance[i, j]) + " ");
                }
                Console.WriteLine();
            }
        }

        private static string ToString(int n)
        {
            if (n < 10) return "0" + n;
            return n + "";
        }
    }
}