[小明学算法]6.字符串匹配算法---KMP

      static void Main(string[] args)
        {


            char[] pattern = { ‘a‘, ‘b‘, ‘c‘, ‘a‘, ‘b‘, ‘c‘, ‘d‘, ‘e‘, ‘f‘ };
            int[] table = new int[pattern.Length];
            cal_next_table(pattern, table);

            Console.Read();
        }

        static void cal_next_table(char[] pattern,int[] table)
        {
            //设Table[0]为哨兵
            table[0] = 1;
            Print(pattern);
            Print(table);
            for (var i = 1; i < pattern.Length; i++)
            {            
                table[i] = table[i - 1];
                var t1 = GetSubArr(pattern, 0, i);

                //检测t2(注意起点)是否和t1头部重合,重合则break
                for(var j=table[i];j<i;j++)
                {
                    var t2 = GetSubArr(t1, j, i );
                    Print(t1);
                    if (!strcncmp(t1, t2))
                    {
                        table[i]++;
                    }
                    else
                        break;
                }
                Print(t1);

                Print(pattern);
                Print(table);
            }
           
        }

        static char[] GetSubArr(char[] pattern,int start,int end)
        {
            char[] t = new char[end - start];
            for(int i=0;i<t.Length;i++)
            {
                t[i] = pattern[i + start];
            }

            return t;
        }

        static void Print(Array arr)
        {
            foreach(var a in arr)
            {
                Console.Write(a + " ");
            }
            Console.WriteLine();
        }

        static bool strcncmp(char[] arr1,char[] arr2)
        {
            for(var i=0;i<arr2.Length;i++)
            {
                if (arr1[i] != arr2[i])
                    return false;
            }

            return true;
        }

a b c a b c d e f
1 0 0 0 0 0 0 0 0
a
a b c a b c d e f
1 1 0 0 0 0 0 0 0
b
a b
a b c a b c d e f
1 1 2 0 0 0 0 0 0
c
a b c
a b c a b c d e f
1 1 2 3 0 0 0 0 0
a
a b c a
a b c a b c d e f
1 1 2 3 3 0 0 0 0
a b
a b c a b
a b c a b c d e f
1 1 2 3 3 3 0 0 0
a b c
a b c a b c
a b c a b c d e f
1 1 2 3 3 3 3 0 0
a b c d
b c d
c d
d
a b c a b c d
a b c a b c d e f
1 1 2 3 3 3 3 7 0
e
a b c a b c d e
a b c a b c d e f
1 1 2 3 3 3 3 7 8