怎么就没关系了？
by t162 @ 2019-05-29 19:57:18
ORZ，大佬$\Theta(1)$数学求解
by lukelin @ 2019-05-29 20:00:21
是因为可以用主席树搞吧
by NaCly_Fish @ 2019-05-29 20:48:46
捉鰰
by algobase @ 2020-05-14 13:20:34