Advent of Code, in Rust

Year	Stars	When
2021	50 🌟	Nov. 2022
2022	50 🌟	Dec. 2022
2020	50 🌟	Feb. 2023
2015	42 🌟	On a break
2023	50 🌟	Dec. 2023

About this workspace

My main goal here is to practice and write idiomatic Rust solving "Advent of Code" puzzles. Any of my solvers should parse the input (nothing by hand) and not panic but return an error.

In this workspace, packages are:

• "common" which defines Year, Day, Part enums used in other packages and reexport "anyhow" and an extended "rustc-hash". It also has a prelude for convenience.
• "solvers" is a library for all my solutions and utilities plus a binary to run them from the command line.
• "web" for simple interactions with adventofcode.com.

Performance

The Rust Performance Book is a must-read.

Faster tests

Using "cargo-nextest", run tests in release mode is 70% to 120% faster. And reports are so much cleaner.

cargo nextest run -r [--run-ignored [ignored-only|all]]

Faster solvers

I use the flamegraph crate to easily detect where my code is not efficient enough (basic usage).

Here is what I learnt so far:

• Heap-allocation: prevent it or avoid as much reallocation as possible with:
  • methods like with_capacity, reserve and insightful values ;
  • shared vec/hashmap/... like fn job(..., &mut shared: HashMap<Data, usize>).
• Hash less data. Use a faster hasher? Or avoid hashing entirely when possible (eventually use vectors when possible).
• Know the methods of the data structure you use.
• Use u32 instead of usize when possible on a 64 bits target.
• Otherwise change... the data structure you use OR the entire algorithm, there is fun in starting from scratch again.

cli-runner usage

Arguments: [<year [20]15...> [<day 1...25> [<part 1 2> [<input 0...>]]]]

• When no input index is given, the solver runs on all inputs.
• When no part is given, the solver runs on both parts.
• When no day is given, the solver runs on all available days/parts (only big inputs).
• When no year is given, the solver runs on all available years/days/parts (only big inputs).

web usage

The session cookie can be hold in an environment variable (AOC_TOKEN by default), in a text file or be given manually.

cargo web [--token <TOKEN>] <YEAR> <DAY> open [--calendar] [--description] [--input]
cargo web [--token <TOKEN>] <YEAR> <DAY> download [--calendar <FILEPATH>] [--description <FILEPATH>] [--input <FILEPATH>]
cargo web [--token <TOKEN>] <YEAR> <DAY> submit <PART> <ANSWER>

Roadmap

• Expand/Improve my utilities.
• Solve puzzles & faster.
• Maybe make a Terminal User Interface.
• Maybe make terminal visualizations, in my "solvers" library behind a feature flag.