@[guozhetao](/user/669924) 快排不是稳定排序，需要把第一个 cmp 变成：
```cpp
bool cmp(c x,c y) {
return x.num != y.num?x.num<y.num:x.id<y.id;
}
```
by World_Creater @ 2022-09-20 15:53:42
@[World_Creater](/user/122836) 感谢，AC了
by guozhetao @ 2022-09-21 08:21:08