https://docs.google.com/presentation/d/1Bl-PTBfa5sp1vM1l0OSMpK_0JFQ-MT6je4O26-9ffpg/edit?usp=sharing
cs61b 2020 lec16 ds2 adts, sets, maps, binary search trees - Google Slides
CS61B, 2019 Lecture 16: ADTs and BSTs Abstract Data Types Binary Search Tree (intro) BST Definitions BST Operations Sets vs. Maps, Summary
binary search trees