摘要：
You are given an undirected graph consisting of n vertices and edges. Instead of giving you the edges that exist in the graph, we give you m unordered 阅读全文
摘要：
This year Alex has finished school, and now he is a first-year student of Berland State University. For him it was a total surprise that even though h 阅读全文
摘要：
Apart from plush toys, Imp is a huge fan of little yellow birds! To summon birds, Imp needs strong magic. There are n trees in a row on an alley in a 阅读全文