开 long long，把 N 开到 2e6 都是一样的结果
by llxsmy_forever @ 2024-04-26 13:32:27
@[llxsmy_forever](/user/664779) `bt(1,1,n);`是 `bt(1,1,m)`
by __zaa__ @ 2024-04-26 14:18:59
@[__zaa__](/user/716965) 谢谢，已关注
by llxsmy_forever @ 2024-04-26 22:44:15