感谢，蒟蒻 $n$ 没开ll。
by OcTar @ 2023-10-12 11:01:40
还有就是尽量先除再乘，防止爆 long long
by Azote @ 2024-01-08 15:38:40
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by zdnzkzl @ 2024-02-29 20:51:38
谢谢
by HxDlBbCo877 @ 2024-04-11 13:23:31