[提交记录](https://www.luogu.com.cn/record/86730972)
by huangkerui @ 2022-09-16 15:09:11
@[huangkerui](/user/478118) UB+初始化不干净
应该
```cpp
const int M=4e6+10;
```
然后初始化：
```cpp
memset(head,0,sizeof(head));
cnt=0,tot=0;
memset(f,0,sizeof(f));
memset(head,0,sizeof(head));
```
by _LiWenX_ @ 2022-09-16 15:55:46
可以了，谢谢！
by huangkerui @ 2022-09-16 15:59:24