摘要： A. Dima and Friendstime limit per test2 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputDima and his friends have been playing hide and seek at Dima's place all night. As a result, Dima's place got messy. In the morning they decided that they need to clean th 阅读全文

摘要： D. Zero Treetime limit per test2 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputA tree is a graph with n vertices and exactly n - 1 edges; this graph should meet the following condition: there exists exactly one shortest (by number of edges) path between any pair of 阅读全文