学步园

        /// <summary>

        /// Brute-Force算法

        /// </summary>

        /// <param name="s">父串</param>

        /// <param name="t">子串</param>

        /// <returns>子串在父串的索引</returns>
        public static int BF(string s, string t)

        {

            int i = 0, j = 0 ;

            for(;i < s.Length && j <t.Length;)

            {

                if(s[i] == t[j])

                {

                    i++;

                    j++;

                }

                else

                {

                    i = i - j + 1;

                    j = 0;

                }

            }

            if(j == t.Length)

            {

                return i - t.Length;

            }

            else

            {

                return -1;

            }

            

        }