你可以把$vis$那几行换一下：
```c++
f[find(e[i].a)] = find(e[i].b+n);
f[find(e[i].b)] = find(e[i].a+n);
```
by Salt_conch @ 2024-04-09 20:28:50
然后就是开两倍，还有$e$数组和$f$数组开大一点
```c++
for(int i = 1;i <= 2*n;i ++) f[i] = i;
```
by Salt_conch @ 2024-04-09 20:31:29