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对正整数n，欧拉函数是少于或等于n的数中与n互质的数的数目。此函数以其首名研究者欧拉命名，它又称为Euler's totient function、φ函数、欧拉商数等。例如：φ(8) = 4（Phi(8) = 4），因为1,3,5,7均和8互质。 对正整数n，欧拉函数是少于或等于n的数中与n互质的数 阅读全文
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现在有好多种砝码，他们的重量是 w0,w1,w2,... 每种各一个。问用这些砝码能不能表示一个重量为m的东西。 样例解释：可以将重物和3放到一个托盘中，9和1放到另外一个托盘中。 现在有好多种砝码，他们的重量是 w0,w1,w2,... 每种各一个。问用这些砝码能不能表示一个重量为m的东西。 样例 阅读全文
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Pashmak has fallen in love with an attractive girl called Parmida since one year ago... Today, Pashmak set up a meeting with his partner in a romantic 阅读全文
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Recently Anton found a box with digits in his room. There are k2 digits 2, k3 digits 3, k5 digits 5 and k6 digits 6. Anton's favorite integers are 32 阅读全文
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Someday, Drazil wanted to go on date with Varda. Drazil and Varda live on Cartesian plane. Drazil's home is located in point (0, 0) and Varda's home i 阅读全文
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A and B are preparing themselves for programming contests. To train their logical thinking and solve problems better, A and B decided to play chess. D 阅读全文
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Our good friend Mole is trying to code a big message. He is typing on an unusual keyboard with characters arranged in following way: qwertyuiopasdfghj 阅读全文
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What joy! Petya's parents went on a business trip for the whole year and the playful kid is left all by himself. Petya got absolutely happy. He jumped 阅读全文
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So, the New Year holidays are over. Santa Claus and his colleagues can take a rest and have guests at last. When two "New Year and Christmas Men" meet 阅读全文
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Simon and Antisimon play a game. Initially each player receives one fixed positive integer that doesn't change throughout the game. Simon receives num 阅读全文
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Bob is preparing to pass IQ test. The most frequent task in this test is to find out which one of the given n numbers differs from the others. Bob obs 阅读全文
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Little Chris is bored during his physics lessons (too easy), so he has built a toy box to keep himself occupied. The box is special, since it has the 阅读全文
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Polycarp has just invented a new binary protocol for data transmission. He is encoding positive integer decimal number to binary string using followin 阅读全文
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Kirito is stuck on a level of the MMORPG he is playing now. To move on in the game, he's got to defeat all n dragons that live on this level. Kirito a 阅读全文
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Duff is addicted to meat! Malek wants to keep her happy for n days. In order to be happy in i-th day, she needs to eat exactly ai kilograms of meat. T 阅读全文
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A - ABCxxx Time limit : 2sec / Memory limit : 256MB Score : 100 points Problem Statement This contest, AtCoder Beginner Contest, is abbreviated as ABC 阅读全文