AdventOfCode2021 :christmas_tree:

Solutions to all 25 AoC 2021 problems in Rust, using less than 100 lines per day, with a total execution time of less than a second :crab:

All solutions are quite short and efficient while still being readable and idiomatic. The code emits zero clippy warnings and has a total execution time of about 0.85s!

See timings.md for execution time and output of each solution.

Thanks again for another amazing year of AoC, especially the subreddit community and of course @ericwastl! Overall, I thought 2021 was one of the best years yet. The difficult was just right. Definitely harder than 2020 I thought but not more than 2019.

Usage

cargo run --release --bin DAY # run a specific day
cargo run --release           # run all days

Other years

• 2020 in Rust :crab:
• 2019 in Rust :crab:
• 2018 in Python :snake:
• 2017 in Haskell λ
• 2016 in OCaml :camel:
• 2015 in Clojure λ

Leaderboard placings

The puzzles unlock at 06:00 in the morning in my timezone. This is the second year in a row I've set an alarm for 5:50 for 25 days in a row to complete for leaderboard placings (except day 11 when I overslept)!

Went very well this year compared to last year, top 1000 for 18/25 days. Set a new personal best of 153!