Problem description Petya loves lucky numbers. Everybody knows that lucky numbers are positive integers whose decimal representation contains only the ...
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其他好文 时间：
2018-06-02 13:27:10
阅读次数：
218
Problem description Petya loves lucky numbers. Everybody knows that positive integers are lucky if their decimal representation doesn't contain digits ...
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其他好文 时间：
2018-06-01 20:41:17
阅读次数：
237
Problem description Petya loves football very much. One day, as he was watching a football match, he was writing the players' current positions on a p ...
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其他好文 时间：
2018-05-29 16:19:43
阅读次数：
193
Description Jamie loves sleeping. One day, he decides that he needs to wake up at exactly hh:?mm. However, he hates waking up, so he wants to make wak ...
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其他好文 时间：
2018-05-25 16:54:27
阅读次数：
224
好久没有写反演了 感觉不会了 首先推一个经典的式子啊 $$ans = \sum_{D=1}^{n}\sum_{d|D}f(d)\mu(\frac{D}{d})\frac{n}{D}\frac{m}{D}$$ 记$g(D) = \sum_{d|D}f(d)\mu(\frac{D}{d})$ 结论挺好找 ...
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其他好文 时间：
2018-05-13 19:07:52
阅读次数：
167
求$\sum_{i=1}^n \sum_{j=1}^m lcm(i,j)^{gcd(i,j)}$ ...
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其他好文 时间：
2018-05-06 20:05:14
阅读次数：
168
Discription Levko loves strings of length n, consisting of lowercase English letters, very much. He has one such string s. For each string t of length ...
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其他好文 时间：
2018-05-03 14:27:59
阅读次数：
185
3569: DZY Loves Chinese II Description 神校XJ之学霸兮，Dzy皇考曰JC。 摄提贞于孟陬兮，惟庚寅Dzy以降。 纷Dzy既有此内美兮，又重之以修能。 遂降临于OI界，欲以神力而凌♂辱众生。 今Dzy有一魞歄图，其上有N座祭坛，又有M条膴蠁边。 时而Dzy狂WA ...
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其他好文 时间：
2018-05-03 01:05:02
阅读次数：
255
Petya loves lucky numbers. Everybody knows that lucky numbers are positive integers whose decimal representation contains only the lucky digits 4 and ...
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编程语言 时间：
2018-05-01 23:47:27
阅读次数：
350
Discription The Little Elephant loves permutations of integers from 1 to n very much. But most of all he loves sorting them. To sort a permutation, th ...
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其他好文 时间：
2018-05-01 20:51:41
阅读次数：
187
