Tree Balancing

You are given a rooted tree of N vertices, the root is at vertex 1. The i-th edge has two parameters associated with it, Ci denoting the cost of the edge and parameter Di. You want to make cost of all the paths from the root to any leaf having equal costs. Cost of a path is sum of costs of all the edges on the path. For that, you can increase or decrease cost of any edge. The time taken in cha