@[WhileTrueRP](/user/373198) 首先有个小小的问题，
```
int add(int u,int v){
a[u].push_back(v);
a[v].push_back(u);
}
```
应为 `void add()`?
by Greenzhe @ 2023-08-29 18:10:27
剩下没调出来awa
by Greenzhe @ 2023-08-29 18:18:58
兄弟你最后ac了没，我也只过1和6
by idiotgoose @ 2023-10-24 17:24:17
哦我知道了，差分错了
by idiotgoose @ 2023-10-24 19:13:59
**应该从叶子节点加上去，而不是从根节点加下来**，比如加这条红色的线，会导致红色的圆圈也会被加上 ~~图画得不好凑合一下~~ https://cdn.luogu.com.cn/upload/image_hosting/eedv6k4v.png
by wuchenan @ 2023-11-14 09:51:30