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Problem description Alyona's mother wants to present an array of n non-negative integers to Alyona. The array should be special. Alyona is a capriciou 阅读全文
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Problem description After the lessons n groups of schoolchildren went outside and decided to visit Polycarpus to celebrate his birthday. We know that 阅读全文
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Problem description Linear Kingdom has exactly one tram line. It has n stops, numbered from 1 to n in the order of tram's movement. At the i-th stop a 阅读全文
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Problem description Year 2118. Androids are in mass production for decades now, and they do all the work for humans. But androids have to go to school 阅读全文
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Problem description Crazy Town is a plane on which there are n infinite line roads. Each road is defined by the equation aix + biy + ci = 0, where ai 阅读全文