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3297: [USACO2011 Open]forgot Description 发生了这么多，贝茜已经忘记了她cowtube密码。然而，她记得一些有用的信息。首先，她记得她的密码（记为变 量P）长度为L（1 <= L<=1,000）字符串，并可以被分成 一个或多个词（不一定是唯一的），词来自于字典 阅读全文
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3296: [USACO2011 Open] Learning Languages Description 农夫约翰的N（2 <= N<=10,000）头奶牛，编号为1.. N，一共会流利地使用M（1<= M <=30,000）种语言，编号从1 .. M.，第i头，会说K_i（1 <= K_i<= 阅读全文
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Graph constructive problems are back! This time the graph you are asked to build should match the following properties. The graph is connected if and 阅读全文
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Petya has a simple graph (that is, a graph without loops or multiple edges) consisting of n n vertices and m m edges. The weight of the i i -th vertex 阅读全文
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You are given array a a of length n n . You can choose one segment [l,r] [l,r] (1≤l≤r≤n 1≤l≤r≤n ) and integer value k k (positive, negative or even ze 阅读全文