These are my solutions to Advent of Code 2021 in R.
R 4.1.2 was used. Run renv::restore() to recreate the package environment from the lockfile.
The goal was to mainly use a combination of base R and the data.table package.
data.table 1.14.3 or higher is required (currently not yet on CRAN, so install from Github).
To run all code, source run_all.R.