These are my solutions to Advent of Code 2019. All code is base R (3.6.2), the only exception being Day 22 where {gmp} is needed.
To install gmp on your Debian-based system prior to installing the R package do sudo apt-get install libgmp-dev
Each script can be sourced independently and will check against the correct solution. Intermediate outputs are suppressed by default, prompts are automatically filled in.
run_all.R runs all scripts in order and outputs execution times.