Solutions for Advent of Code puzzles are organised by language, then year, then day. Each day is runnable on its own and does not depend on solutions for other days.
Using this as an opportunity to get more familiar with Rust, so not necessarily (well, unlikely) very clean code.
Generating fresh rust project for each day by
cargo new --bin --vcs none --edition 2018 d01
The input files are encrypted, but can be kept locally unencrypted as that is what the programs expect. To encrypt run
./lock.bash <GPG RECIPIENT>