Word Search（leetcode）

Word Search（leetcode）

Given a 2D board and a word, find if the word exists in the grid.
The word can be constructed from letters of sequentially adjacent cell, where "adjacent" cells are those horizontally or vertically neighboring. The same letter cell may not be used more than once.
For example,

Given board =

[
['A','B','C','E'],
['S','F','C','S'],
['A','D','E','E']
]

word = 

"ABCCED"

, -> returns 

true

,
word = 

"SEE"

, -> returns 

true

,
word = 

"ABCB"

, -> returns 

false

.

代码：
class Solution {
public:
bool exist(vector<vector<char>>& board, string word) {
int x = board.size();
int y = board[0].size();
bool result = false;
for(int i = 0; i < x; i++) {
for (int j = 0; j < y; j++) {
result = isFound(board, i, j, word.c_str());
if (result)
return true;
}
}
return result;
}
bool isFound(vector<vector<char>>& board, int i, int j, const char* word) {
int x = board.size();
int y = board[0].size();
if (*(word) == '\0')
return true;
if (i < 0 || j < 0 || i >= x || j >= y || board[i][j] != *word)
return false;
char c = board[i][j];
board[i][j] = '#';
if (isFound(board, i-1, j, word+1) ||
isFound(board, i, j+1, word+1) ||
isFound(board, i+1, j, word+1) ||
isFound(board, i, j-1, word+1))
return true;
board[i][j] = c;
return false;
}
};

896c