<https://www.luogu.com.cn/discuss/525209>
by hswfwkj @ 2023-09-13 12:45:46
@[Alex_Wei](/user/123294)
by hswfwkj @ 2023-09-13 12:46:23
@[hswfwkj](/user/374318) 改成 $1\leq k\leq 10 ^ 3$ 了，应该没问题吧？
by Alex_Wei @ 2023-09-15 09:44:35