BM算法学习

    // 偷懒就没使用预处理的方式
    int getLastIndex(int patternIndex, string pattern, char inStrChar)
    {
        //在pattern中根据index取得在index前=char的index
        for (int i = patternIndex-1; i >= 0; --i)
        {
            if (pattern[i] == inStrChar)
            {
                return i;
            }
        }
        return -1;
    }

    int BM(string inStr, string pattern)
    {
        int lastIndex = pattern.Length - 1;
        for (int i = lastIndex; i < inStr.Length; )
        {
            for (int k = 0; k < pattern.Length;)
            {
                if (inStr[i-k] == pattern[lastIndex-k])
                {
                    k++;
                    if (k == lastIndex)
                    {
                        return i;
                    }
                }
                else
                {
                    int move = lastIndex - k - getLastIndex(lastIndex - k, pattern, inStr[i - k]);
                    i += move;
                    break;
                }
            }
        }
        return -1;
    }