So I've just started going through LC's "Explore" content to refresh myself on some DS/A topics (and pick up stuff I haven't learned in-depth). I started with the "Graphs" topic and went over the disjoint set sections. All good! The content made sense and it was semi-clear how the lesson pertained to the exercise (number of provinces). My solution was close to the provided solution, but had a few miscalculations. I understood what I missed after having a look [at the solution].

Next, I tried to tackle the "Graph Valid Tree" exercise. I decided to not give in as easily and spend more time than I did with the first exercise. I was sure, with some more logic for corner cases, I could get some sort of working solution. I spent almost two hours trying to understand what I was missing, only to find the proposed solution uses "depth-first search"... which is covered in later lessons. A bit frustrating... but oh well.

Anyway, is there some prescribed order for the DS&A topics covered in the "Explore" section of the site? Ideally I'd like to avoid similar scenarios--i.e., encountering problems that will be extremely difficult to solve without context or useful information that can be found in another chapter.