rustmas

Rust tooling for Advent of Code. It downloads your inputs, runs your solutions, checks the answers against an independent solver, and submits them for stars.

No solutions ship with it. Scotty's own are on the scadoshi branch if you want worked examples.

Quick start

1. Copy your session cookie from adventofcode.com using your browser's dev tools.
2. Paste it into .env:

cp .env.template .env    # paste the cookie into COOKIE=

3. Run a day:

cargo run fetch -y 2015 -d 1              # download one puzzle into cache/
cargo run solve -y 2015 -d 1              # run your solution offline
cargo run solve -y 2015 -d 1 --validate   # check answers against the solver
cargo run solve -y 2015 -d 1 --submit     # check, then send for stars

Drop -y or -d to run every year or day. Add --release on brute-force days.

--submit only sends answers the solver agrees with. Wrong ones cost an escalating cooldown.

Writing a day

Copy the template to start a year:

cp -r src/lib/domain/solution/year_template src/lib/domain/solution/year_2015

Each part returns Answer::solved(value), Answer::Visual(art), or Answer::None. The template starts both parts at Answer::Unwritten.

fn part_one(&self) -> anyhow::Result<Answer> {
    Ok(Answer::solved(self.input.len().to_string()))
}

Then register the year:

• Add pub mod year_2015; to solution/mod.rs.
• Add an arm to solver_for in src/lib/inbound/solve/mod.rs. Copy the commented example there.

Helpers shared across days go in solution/common/.

Reading the output

year 2015 day 1 in 12.707µs (3.291µs parsing)
  part one: 138 (correct) [7.125µs]
  part two: 1771 (correct) [2.291µs]

Note	Meaning
nothing	Solved offline, unchecked
correct	The solver agrees
high, low, incorrect	The solver disagrees, so nothing was submitted
new star / starred	Accepted now / already solved
not logged in	Cookie missing or expired
unsupported	The solver can't do this puzzle
rate limited, ...	Advent of Code refused to grade
(none) / (unwritten)	No answer exists (day 25 part two) / not written yet
error: ...	The part failed; the other still ran

Multi-day runs end with total and average parse and solve times, plus the slowest part. Timings never include the network.

Re-running fetch never re-downloads. Without a cookie, solve and --validate still work offline. More in context/.

Credits

--validate and --submit rely on Fredrik Fornwall's advent-of-code solver (API).

Advent of Code is by Eric Wastl. Per the about page, this tool caches inputs, keeps puzzle text out of git, and identifies itself.

License

MIT. See LICENSE.