##### 把
```cpp
if(!(px>=sx&&px<=fx&&py>=sy&&py<=fy&&!vis[px][py]))continue;
```
改成
```cpp
if (px<1|| px > n||py<1 || py > m|| vis[px][py])continue;
```
##### 然后把vis[x][y] = 0;转移到dfs的循环后面
by HUFT @ 2022-11-04 20:07:34
@[HUFT](/user/725561) 栓Ｑ大佬帮忙，ＡＣ啦
by ECNUAT_LZX @ 2022-11-07 16:14:29