dfs C++代码

 class Solution {
public:

int flag = 0; //标记是否成功搜索到word
int map[205][205]; //标记是否进入过该格子
int rows, columns; 
int moverow[4] = {0, 0, -1, 1};
int movecol[4] = {1, -1, 0, 0}; //四个移动方向
bool hasPath(vector<vector<char> >& matrix, string word) {
    rows = (int) matrix.size();
    columns = (int) matrix[0].size();
    memset(map, 0, sizeof(map));
    for(int i = 0; i < rows; i ++)
        for(int j = 0; j < columns; j ++)
            dfs(matrix, 0, word, i, j);
    if(flag) return 1;
    else return 0;
}
void dfs(vector<vector<char> >& matrix, int lnow, string word, int x, int y) {
    if(flag == 1) return;
    if(lnow == word.length()) {
        flag = 1;
        return;
    }
    if(x < 0 || y < 0 || x >= rows || y >= columns || matrix[x][y] != word[lnow] || map[x][y] != 0) return;
    map[x][y] = 1; //当前格子已搜索过
    lnow ++; //当前格子里字母符合查找需要
    for(int i = 0; i < 4; i ++) {    
        int xx = x + moverow[i], yy = y + movecol[i];
        dfs(matrix, lnow, word, xx, yy); 
    }
    lnow --;
    map[x][y] = 0; //恢复
}

};