Post Tree

You are given a rooted tree on N vertices. The nodes are numbered from 1 to N, and Node 1 is the root. Each node u has an associated value attached to it: Au. For each vertex v, we consider the path going upwards from v to the root. Suppose that path is v1, v2, .., vk, where v1 = v and vk = 1. The cost of any node on this path is equal to the minimum value among all the nodes to its left in the p