摘要：There are N villages, which are numbered from 1 to N, and you should build some roads such that every two villages can connect to each other. We say t 阅读全文

摘要：You are a member of the space station engineering team, and are assigned a task in the construction process of the station. You are expected to write 阅读全文

摘要：The Head Elder of the tropical island of Lagrishan has a problem. A burst of foreign aid money was spent on extra roads between villages some years ag 阅读全文