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求$\sum_{i=1}^n \sum_{j=1}^m lcm(i,j)^{gcd(i,j)}$ 阅读全文
posted @ 2018-05-06 18:37
VisJiao
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求$\sum_{i=1}^n\sum_{j=1}^m [\sigma_1(gcd(i,j))\leq a]\sigma_1(gcd(i,j))$,莫比乌斯反演+树状数组 阅读全文
posted @ 2018-05-06 17:01
VisJiao
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求$\sum_{i=1}^n\sum_{j=1}^m\sigma_0(ij)$ 阅读全文
posted @ 2018-05-06 16:31
VisJiao
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Cf787D的简单变体 阅读全文
posted @ 2018-05-06 15:52
VisJiao
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