@Simd It looks like that code is actually doing almost the same thing as the Fenwick tree! (The differences are that the tree is irregular and the midpoints are handled specially.)
I just realised that lyxal could literally edit any message he wants to. Somehow this never occurred to me despite the fact I've seem him edit messages from Vyxal Bot and New Posts before
Scenario: I run across an old answer of mine. Since I posted it, both I as a golfer and the language it's written in have gotten much better. Do I: 1) Golf the answer using modern language features? 2) Post a new answer using modern language features and leave the old answer alone? 3) Golf the answer but stick to old language features (and also maybe post another answer using modern language features)?
I'm guessing the answer is "do whatever you want, it's your answer," but what would you all do in this situation?