题解 | #矩阵中的路径#

典型的DFS，深度优先搜索

class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param matrix char字符型vector<vector<>> 
     * @param word string字符串 
     * @return bool布尔型
     */
    int n,m,l;
    bool ans = false;
    string w;//定义一些类内全局变量
    bool hasPath(vector<vector<char> >& matrix, string word) {
        // write code here
        m = matrix.size();
        if(m == 0)return false;
        n = matrix[0].size();
        if(n == 0)return false;
        l = word.size();
        vector<vector<bool>> visit(m, vector<bool>(n, false));
        w = word;
        for(int i = 0; i < m; i++){
            for(int j = 0; j < n; j++){
                if(ans)return ans;
                if(matrix[i][j] == word[0]){
                    dfs(matrix, visit, i, j, 0);
                }
            }
        }
        return ans;
    }
    void dfs(vector<vector<char>> &matrix, vector<vector<bool>> visit, int i, int j, int k){
        if(0<=i && i < m && 0<=j && j<n && visit[i][j] == false){
            if(matrix[i][j] == w[k]){
                visit[i][j] = true;
                if(k == l-1){
                    ans = true;
                    return;
                }
                dfs(matrix, visit, i-1, j, k+1);
                dfs(matrix, visit, i+1, j, k+1);
                dfs(matrix, visit, i, j-1, k+1);
                dfs(matrix, visit, i, j+1, k+1);
            }
        }
    }
    
};