摘要: 20250426 NOI 模拟赛 Link Problem A. Varphi 由 \(\varphi(n)=n\prod_{p_i\in \mathbb{P}\land p_i\mid n}\frac{p_i-1}{p_i}\),得 \[\varphi(xy)=\varphi(x)\varphi( 阅读全文
posted @ 2025-04-29 21:24 XP3301_Pipi 阅读(22) 评论(0) 推荐(0)
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