KMP算法實現

class Program
{
static void GetNextVal(string str, int [] next)
{
int i = 0;
int j = -1;
next[0] = -1;
while (i < str.Length - 1)
{
if (j == -1 || str[i] == str[j])
{
i++;
j++;
next[i] = j;
}
else
{
j = next[j];
}
}

}

    static int KMP(string zstr, string mstr)
    {
        int i, j;
        int[] next = new int[mstr.Length];
        GetNextVal(mstr, next);
        i = 0;
        j = 0;
        while (i < zstr.Length && j < mstr.Length)
        {
            if (j == -1 || zstr[i] == mstr[j])
            {
                ++i;
                ++j;
            }
            else
            {
                j = next[j];
            }
        }
        if (j == mstr.Length)
            return i - mstr.Length;
        return -1;
    }




    static void Main(string[] args)
    {
        string zstr, mstr;
        zstr = Console.ReadLine();
        mstr = Console.ReadLine();
        int pos1;
        pos1 = KMP(zstr, mstr);
        if (pos1 == -1) Console.WriteLine("沒有匹配的字符串！");
        else Console.WriteLine(pos1);
        Console.Write("請按任意鍵繼續。。");
        Console.ReadKey(true);
    }
}