Brute-Force算法

using System;
namespace ConsoleApplication10
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine(index("cbbcbcbb","acbc"));

            Console.WriteLine(index("cbbcbcbb","bcb"));

            Console.ReadLine();
        }


        static int index(string s ,string t)
        {
            int i = 0, j = 0, k;

            while (i<s.Length&&j<t.Length)
            {
                if (s[i]==t[j])
                {//如果相等继续匹配
                    i++;
                    j++; 
                }
                else
                {//不相等时回溯 
                    i = i - j + 1;
                    j = 0;
                }
            }
            if (j>=t.Length)
            {//匹配成功
                k = i - t.Length;
            }
            else
            {
                k=-1;
            }
            return k;
        }
    }
}