Advent of Code 2021 in Rust

My Advent of Code 2021 solutions in the Rust programming language. This repository holds a separate Rust project for each day and part.

I attempt to develop a standalone, elegant, compact and fast solution for each problem (two each day).

Previous year I did the same, solving everything in under a second:

• https://timvisee.com/blog/solving-aoc-2020-in-under-a-second/
• https://github.com/timvisee/advent-of-code-2020

Timings

Here is how long each solution runs. All solutions are measured (non scientifically) in bench.rs on an AMD Ryzen 9 5900X (24) @ 3.7GHz machine running Linux.

Run solutions

Each Rust project contains a input.txt file, holding the puzzle input. Simply run the project to see the solution appear.

# Switch to day 1a, and run it
cd day01a
cargo +nightly run --release

# or run everything in parallel
cd ../runner
cargo +nightly run --release --bin runner-par

# or benchmark every day
cd ../runner
cargo +nightly run --release --bin bench

Some solutions require Rust Nightly, that's why +nightly is included.

Other years

• 2025
• 2024
• 2023
• 2022
• 2021 (current)
• 2020
• 2019
• 2018
• 2017

License

This project is released under the GNU GPL-3.0 license. Check out the LICENSE file for more information.