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D. Make a Permutation! Ivan has an array consisting of n elements. Each of the elements is an integer from 1 to n. Recently Ivan learned about permuta 阅读全文
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B. Train Seats Reservation You are given a list of train stations, say from the station 1 to the station 100. The passengers can order several tickets 阅读全文
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C. Mahmoud and Ehab and the xor Mahmoud and Ehab are on the third stage of their adventures now. As you know, Dr. Evil likes sets. This time he won't 阅读全文
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Mahmoud and Ehab and the bipartiteness Mahmoud and Ehab continue their adventures! As everybody in the evil land knows, Dr. Evil likes bipartite graph 阅读全文
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Bob has a not even coin, every time he tosses the coin, the probability that the coin's front face up is qp(qp≤12)\frac{q}{p}(\frac{q}{p} \le \frac{1} 阅读全文
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D - joisino's travel Problem Statement There are N towns in the State of Atcoder, connected by M bidirectional roads. The i-th road connects Town Ai a 阅读全文
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日天学长向妹子表白了，妹子说：“日天你那么聪明，回答我一个问题就答应你。你告诉我，L位K进制数有多少个？”日天表示这个问题太简单了，要求提高难度。妹子想了想说：“那么我增加一个要求，一个满足要求的L位K进制数，任意两位相邻的数字相减的绝对值不能等于一，你能告诉我，有多少个满足条件的L位K进制数么？” 阅读全文
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G. Bathroom terminal Smith wakes up at the side of a dirty, disused bathroom, his ankle chained to pipes. Next to him is tape-player with a hand-writt 阅读全文
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A. Arpa and a research in Mexican wave Arpa is researching the Mexican wave. There are n spectators in the stadium, labeled from 1 to n. They start th 阅读全文
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C - 4-adjacent Time limit : 2sec / Memory limit : 256MB Score : 400 points Problem Statement We have a sequence of length N, a=(a1,a2,…,aN). Each ai i 阅读全文