Let's give the Advent of Code a try! 2019 is my first year checking it out, and I solved all of day one from within IEx.
It's also interesting to see everyone else's solutions on Github. One of my favorites was Sasa Juric's solution, which used &Stream.iterate/2 to do the recursion necessary in the 2nd part of the problem.
It's not to late to join Advent of Code! Just follow this link:
https://adventofcode.com/
Saša Jurić's solution:
https://github.com/sasa1977/aoc/blob/master/lib/2019/201901.ex
Hexdocs for Stream.iterate
