摘要：
Description It turns out that you are a great fan of rock band AC/PE. Peter learned that and started the following game: he plays the first song of th 阅读全文
摘要：
Description There are N guests checking in at the front desk of the hotel. 2K (0 ≤ 2K ≤ N) of them are twins.There are M rooms available. Each room ha 阅读全文