Are we elegant yet?

[benpigchu]

A long time after my last contribution to this repo, I finally have the mood to look at this repo again.

I see that most problems (except the geometry ones, I guess) are solved now, with or without help from LLMs. And there is an infamous attempt to solve all the problems with the LLM all at once in #234. This makes me feel like there are not so many things to be done here.

Since "Elegantly Solved" is in the full name of this project, I think we should consider the question: "Are the solutions in this repo elegant?"

Here are some thoughts on whether a solution is elegant

1. Basic formatting issues like those listed in Remaining formatting issues #268

2. Descriptive comments explaining the solution, and/or important lemmas split out from the main goals. (which makes it easier to read for a human, or maybe an LLM)

3. Some common lemmas should go to Mathlib (or other libraries) instead of here. There are examples in my old contributions, like geometry lemmas in Imo2023P2 and lemmas on List.splitBy in Imo2022P1

I do not have time to look at every file in this repo, but I think this is a good start for further discussions.