During the contest i have thought about the HLD solution for the problem PHSTREE i have understand about the decomposition of the tree so that we can traverse atmost log n subtree to get the result. But when it comes to answer the query in a single branch we need to use the fenwick tree along with the compressed weight (finding the weight takes logn by binary search), then using the fenwick tree to get the result which also takes logn time so solution should be NlogSquaredN solution.
But when forming the fenwick tree over the single branch i got stuck. I have seen that people used to build the segment tree easily on a single branch of the tree but fenwick tree i do not understand how to do that. Would you please help me clearing my doubts about my approach. I would be very thankful to you.