In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.
Q: A maximum independent set for this data structure can be found in linear time by adding alternating levels. In this structure, any two vertices or nodes must be connected by a single simple path, and thus it is connected and acyclic. By using (*) union-find with disjoint sets, one type of this structure containing all the vertices of a connected graph can be constructed. One variety of this data structure can be used to easily implement a binary search. This structure also comes in red-black and self-balancing-binary varieties. For 10 points, identify this data structure from computer science, a hierarchical graph in which "leaf" nodes ultimately flow from a "root" node.
A:
Science