[https://www.luogu.com.cn/blog/rendex/solution-p1665](https://www.luogu.com.cn/blog/rendex/solution-p1665)
``` cpp
void dfs(int, int);
```
by hellolin @ 2023-03-20 21:59:33
@[hellolin](/user/751017) 瞎了瞎了QwQ,此贴结
by tdogcode @ 2023-03-23 18:50:39