Sorry to hear. Binary trees and related concepts (binary search, for example) are super useful and relatively basic, so they can usually be found in any introduction to algorithm and data structures. If you want to try again, do some studying of that. It will definitely help your programming skills in general!

This, by the way, can easily be the kind of concept that you don't think you need until you learn about it, suddenly figuring out that you've been writing very inefficient code before.