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Problem Description 呃......变形课上Harry碰到了一点小麻烦,因为他并不像Hermione那样能够记住所有的咒语而随意的将一个棒球变成刺猬什么的,但是他发现了变形咒语的一个统一规律:如果咒语是以a开头b结尾的一个单词,那么它的作用就恰好是使A物体变成B物体. Harry已 阅读全文
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A wise man told Kerem "Different is good" once, so Kerem wants all things in his life to be different. Kerem recently got a string s consisting of low 阅读全文
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Every year, hundreds of people come to summer camps, they learn new algorithms and solve hard problems. This is your first year at summer camp, and yo 阅读全文