I was learning DSU tree (also sometimes known as Reachability Tree) recently (see link below) but the most useful application that I could think was for finding maximum/minimum edge in path from some node A to B. However, this can also be done in O(log N) time using Link Cut Trees.
I was wondering if there was anything that can be done by this DSU-tree/Reachability Tree data structure that can't already be done by LCT.
(I am not that well versed with applications of LCT)
Brief idea about Reachability tree for those too bored to read the editorial linked:
Basically, when we iterate over the edges in a tree in order of weight, we also maintain which edge is connecting which component. So suppose an edge e connects components A and B, we create a new node signifying e and attach to its children A and B. Thus it forms a binary tree, with the leaves as the original nodes, and the n-1 internal edges are basically edges in the normal tree.