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Word ss of length nn is called kk -complete if ss is a palindrome, i.e. si=sn+1−isi=sn+1−i for all 1≤i≤n1≤i≤n ; ss has a period of kk , i.e. si=sk+isi 阅读全文
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A positive integer is called composite if it can be represented as a product of two positive integers, both greater than 11 . For example, the followi 阅读全文
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Alice has a cute cat. To keep her cat fit, Alice wants to design an exercising walk for her cat! Initially, Alice's cat is located in a cell (x,y)(x,y 阅读全文
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You are given a rooted tree consisting of nn vertices numbered from 11 to nn . The root of the tree is a vertex number 11 . A tree is a connected undi 阅读全文
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题目描述 Farmer John 计划建造 NNN 个农场，用 N−1N-1N−1 条道路连接，构成一棵树（也就是说，所有农场之间都互相可以到达，并且没有环）。每个农场有一头奶牛，品种为更赛牛或荷斯坦牛之一。 Farmer John 的 MMM 个朋友经常前来拜访他。在朋友 iii 拜访之时，Far 阅读全文
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There are n houses in the village and some bidirectional roads connecting them. Every day peole always like to ask like this "How far is it if I want 阅读全文