@[Walledjc](/user/923022) 若无解，输出0
```cpp
if(ans!=0x3f3f3f3f)cout<<ans;
else cout<<0;
by SW_YM @ 2024-08-28 08:57:14
@[SW_YM](/user/656046) 感谢！！
by Walledjc @ 2024-08-28 11:47:21