For the first time ever I discovered this on time while road tripping. Wanted to toy with Ruby and Nix & flakes.
If you would like to try running the examples, you'll need Nix installed on your system.
From the project root, execute nix develop and Nix will take care of the rest
(installing Ruby, pry, solargraph, etc.).
Each day has it's own .rb file and .txt input (e.g. 1.rb, 1-input.rb), and
contains both solutions for the day. Run with $ ruby 1.rb where 1 is the day
you want to run.