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摘要: There are nn friends who want to give gifts for the New Year to each other. Each friend should give exactly one gift and receive exactly one gift. The 阅读全文
posted @ 2020-01-21 12:07 脂环 阅读(160) 评论(0) 推荐(0) 编辑
摘要: There are nn Christmas trees on an infinite number line. The ii -th tree grows at the position xixi . All xixi are guaranteed to be distinct. Each int 阅读全文
posted @ 2020-01-21 11:58 脂环 阅读(130) 评论(0) 推荐(0) 编辑