rk 好像没啥用？
by pocafup @ 2020-08-29 11:52:46
@[pocafup](/user/219099) 好像是没啥用，但也没影响啊
by MVP_Harry @ 2020-08-29 11:57:24
@[MVP_Harry](/user/306962) 在rangeupdate函数里有锅
```cpp
if (dep[top[x]] > dep[top[y]]) swap(x, y);
```
具体为啥不讲，希望您自己搞明白/kk
by pocafup @ 2020-08-29 12:01:13
@[pocafup](/user/219099) 啊明白了，太谢谢啦！
by MVP_Harry @ 2020-08-29 12:05:45