LeetCode 79. 单词搜索（/dfs）

20230314 顺利通过
原题解

题目

约束

题解

class Solution {
public:
    vector<pair<int, int>> dir{{0, 1}, {0, -1}, {1, 0}, {-1, 0}};
    bool dfs(vector<vector<int>>& visited, vector<vector<char>>&board, string word, int i, int j, int n){
        if(board[i][j] != word[n]){
            return false;
        }else if(n == word.size() - 1){
            return true;
        }
        visited[i][j] = true;
        bool result = false;
        for(const auto &p : dir){
            int newi = i + p.first;
            int newj = j + p.second;
            if(newi >= 0 && newi < board.size() && newj >= 0 && newj < board[0].size()){
                if(!visited[newi][newj]){
                    bool flag = dfs(visited, board, word, newi, newj, n + 1);
                    if(flag){
                        result = true;
                        break;
                    }
                }
            }
        }
        visited[i][j] = false;
        return result;
    }
    bool exist(vector<vector<char>>& board, string word) {
        int m = board.size();
        int n = board[0].size();
        vector<vector<int>> visited(m, vector<int>(n));
        int flag;
        for(int i = 0; i < m; i ++){
            for(int j = 0; j < n; j ++){
                flag = dfs(visited, board, word, i, j, 0);
                if(flag){
                    return true;
                }
            }
        }
        return false;
    }
};