额，少打了个 $\sum$
by cat_lover1 @ 2024-02-25 16:14:47
滚动数组吧，或者进一步的维护一个有一处重叠的轮廓线
by mashduihca @ 2024-02-25 16:15:32
@[mashduihca](/user/494183) 感谢大佬！我试试
by cat_lover1 @ 2024-02-25 20:11:54