题解 | 迷宫寻路

#include<bits/stdc++.h>
using namespace std;
const int N = 101;
char a[N][N];
bool vis[N][N] = {false};
int dx[4] = {1, -1, 0, 0};
int dy[4] = {0, 0, -1, 1};
int n, m;

void dfs(int x, int y) {
    vis[x][y] = true;
    if (x == n && y == m) {
        return;
    }
    for (int i = 0; i < 4; i++) {
        int nx = x + dx[i];
        int ny = y + dy[i];
        if (1 <= nx && nx <= n && 1 <= ny && ny <= m && !vis[nx][ny] &&
                a[nx][ny] == '.') {
            dfs(nx, ny);
        }
    }
}
int main() {
    cin >> n >> m;
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            cin >> a[i][j];
        }
    }
    dfs(1, 1);
    if (vis[n][m])cout << "Yes\n";
    else cout << "No\n";
    return 0;
}