单词搜索 -LintCode

给出一个二维的字母板和一个单词，寻找字母板网格中是否存在这个单词。
单词可以由按顺序的相邻单元的字母组成，其中相邻单元指的是水平或者垂直方向相邻。每个单元中的字母最多只能使用一次。
样例
给出board =

[

“ABCE”,

“SFCS”,

“ADEE”

]

word = “ABCCED”， ->返回 true,
word = “SEE”，-> 返回 true,
word = “ABCB”， -> 返回 false.

#ifndef C123_H#define C123_H#include<iostream>#include<vector>#include<string>using namespace std;class Solution {public:    /**    * @param board: A list of lists of character    * @param word: A string    * @return: A boolean    */    bool exist(vector<vector<char> > &board, string word) {        // write your code here        if (board.empty() || word.empty())            return 0;        for (int i = 0; i < board.size(); ++i)        {            for (int j = 0; j < board[0].size(); ++j)            {                if (searchWord(board, i, j, 0, word))                    return true;            }        }        return false;    }    bool searchWord(vector<vector<char>> &v, int i, int j, int pos, string word)    {        if (pos >= word.size())            return true;        if (i < 0 || j < 0 || i >= v.size() || j >= v[0].size() || v[i][j] != word[pos])            return false;        v[i][j] ^= 100;        bool res = searchWord(v, i + 1, j, pos + 1, word) || searchWord(v, i - 1, j, pos + 1, word) || searchWord(v, i, j + 1, pos + 1, word) || searchWord(v, i, j - 1, pos + 1, word);         v[i][j] ^= 100;        return res;    }};#endif