摘要：
大佬给讲的 自己加了一些备注 阅读全文
摘要：
问题 F: Go Home 题目描述 There is a kangaroo at coordinate 0 on an infinite number line that runs from left to right, at time 0. During the period between t 阅读全文
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问题 K: Dubious Document 题目描述 Snuke loves "paper cutting": he cuts out characters from a newspaper headline and rearranges them to form another string.H 阅读全文