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题目描述 在大学里每个学生，为了达到一定的学分，必须从很多课程里选择一些课程来学习，在课程里有些课程必须在某些课程之前学习，如高等数学总是在其它课程之前学习。现在有 NNN 门功课，每门课有个学分，每门课有一门或没有直接先修课（若课程a是课程b的先修课即只有学完了课程a，才能学习课程b）。一个学生要 阅读全文
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题目背景 随着新版百度空间的上线，Blog 宠物绿豆蛙完成了它的使命，去寻找它新的归宿。 题目描述 给出张 nnn 个点 mmm 条边的有向无环图，起点为 111，终点为 nnn，每条边都有一个长度，并且从起点出发能够到达所有的点，所有的点也都能够到达终点。 绿豆蛙从起点出发，走向终点。 到达每一个 阅读全文
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Problem Statement There is a cave consisting of NN rooms and MM one-directional passages. The rooms are numbered 11 through NN . Takahashi is now in R 阅读全文
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Problem Statement Takahashi will take part in an eating contest. Teams of NN members will compete in this contest, and Takahashi's team consists of NN 阅读全文
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题目描述 某大学有 nnn 个职员，编号为 1…n1\ldots n1…n。 他们之间有从属关系，也就是说他们的关系就像一棵以校长为根的树，父结点就是子结点的直接上司。 现在有个周年庆宴会，宴会每邀请来一个职员都会增加一定的快乐指数 rir_iri，但是呢，如果某个职员的直接上司来参加舞会了，那么 阅读全文
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There are two strings A and B with equal length. Both strings are made up of lower case letters. Now you have a powerful string painter. With the help 阅读全文
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The multiplication puzzle is played with a row of cards, each containing a single positive integer. During the move player takes one card out of the r 阅读全文
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Once Petya read a problem about a bracket sequence. He gave it much thought but didn't find a solution. Today you will face it. You are given string s 阅读全文
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We give the following inductive definition of a “regular brackets” sequence: the empty sequence is a regular brackets sequence, if s is a regular brac 阅读全文
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Gappu has a very busy weekend ahead of him. Because, next weekend is Halloween, and he is planning to attend as many parties as he can. Since it's Hal 阅读全文