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Checkers 参考链接：https://blog.csdn.net/imzxww/article/details/79601824 Problem Little X, Little Y and Little Z are playing checkers when Little Y is anno 阅读全文
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Codeforces 519 E - A and B and Lecture Rooms Problem A and B are preparing themselves for programming contests. The University where A and B study is 阅读全文
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C - CD操作 题目： 在Windows下我们可以通过cmd运行DOS的部分功能，其中CD是一条很有意思的命令，通过CD操作，我们可以改变当前目录。 这里我们简化一下问题，假设只有一个根目录，CD操作也只有两种方式： 1. CD 当前目录名\...\目标目录名 (中间可以包含若干目录，保证目标目录 阅读全文
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How far away ？ problem There are n houses in the village and some bidirectional roads connecting them. Every day peole always like to ask like this "H 阅读全文
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A - Nearest Common Ancestors A rooted tree is a well-known data structure in computer science and engineering. An example is shown below:In the figure 阅读全文