@[MarsTraveller](/user/735797) 破案了：
```cpp
for(big u = 1;u <= n;u++)
{
for(big j = head[u];j != 0;j = edge[u].next)
{
big v = edge[j].to;
if(belong[u] != belong[v])
{
out[belong[u]]++;
}
}
}
```
这里 `j = edge[u].next` 有点乐
by QWQ_123 @ 2024-02-27 18:17:13
@[QWQ_123](/user/740328) 写习惯 `u` 了，下次不写了（
by MarsTraveller @ 2024-02-27 18:43:48