摘要：
You are given a tree (an acyclic undirected connected graph) withNnodes, and edges numbered 1, 2, 3...N-1.We will ask you to perfrom some instructions of the following form:CHANGE i ti: change the cost of the i-th edge to tiorQUERY a b: ask for the maximum edge cost on the path from node a to node b 阅读全文