A hierarchical data pipeline consists of n broadcast stages, numbered 1 to n, arranged in a perfect binary tree rooted at stage 0. Each stage i (for i from 1 to n-1) has a propagation delay to its parent, given by propagation[i-1] (0-indexed).

You want all root-to-leaf propagation paths to have the same total delay. You may only increase individual edge delays -- you may never decrease them. ...