大概就是多项式乘法一次就好了吧。
by w23c3c3 @ 2022-04-27 13:47:43
@[Leap_hash_jperm](/user/574944) `$\mathcal{O}$` 或 `$\Theta$`
by fjy666 @ 2022-04-27 13:56:09
@[Leap_hash_jperm](/user/574944) `$O$`
by rxjdasiwzl @ 2022-04-27 15:45:09