题目链接：http://exam.upc.edu.cn/problem.php?id=4979题目：题目描述Your friend from Manhattan is visiting you in Amsterdam. Because she can only stay for a short while, she wants to see as many tourist attracti...
题目链接：http://exam.upc.edu.cn/problem.php?id=5211题目：题目描述In this problem, we would like to talk about unreachable sets of a directed acyclic graph G = (V, E). In mathematics a directed acyclic graph (...
题目链接：http://exam.upc.edu.cn/problem.php?id=5206题目：题目描述From an evolutionary gene’s-eye perspective, the genes are immortal, and our role, the meaning of life, is to perpetuate the genes. In a few ce...