jorianwoltjer/adventofcode2022

My solutions to Advent of Code 2022 in Rust

Advent of Code 2022

This year I tried every challenge, while learning Rust.
In the end there were only 5/50 puzzles that I missed:

• Day 16 B: Part A was hard enough 😅
• Day 19 A & B: Day 16 with extra steps
• Day 24 B: Should work, but gives the wrong answer. Probably some edge case
• Day 25 B: Only unlocked after completing all 49 other puzzles

I know that if I want to complete all the challenges next year, I'll need to learn more about Depth-first search and how to optimize it. I also realized that the Breadth-first search algorithm is very important to know well, as I used it in quite a few solutions. Other than that, it was pretty successful for only having started with Rust a few months ago.

As the puzzles got harder each day, I eventually started making drawings for a few (15, 16, 18, 21, 22) to test ideas visually instead of trying to imagine it. In some days you'll see a drawing that makes the puzzle or idea more understandable.

Highlights

Some of my most clean and favorite solutions:

• Day 6: Highly optimized buffer reader that would work with a real stream as well
• Day 7: A recursive data structure using Rc<RefCell<>> which wasn't easy in Rust
• Day 12: First time using Breadth-first search and clean code overall
• Day 13: A very clean and rusty compare() function that is fast and minimal
• Day 16 A: After over 6 hours of working on this puzzle, I finally solved it with a big recursive algorithm and some shortcuts
• Day 23: Very simple/short code to solve the whole puzzle with a neat observation
• Day 24 A: A very efficient algorithm that finds the answer in only 60 milliseconds
• Day 25 A: A logical and simple to follow algorithm with detailed comments

New day script

A script to create a new cargo package from the dayN/ template.

./new_day.sh [number]

Flamegraph

Flamegraph allows you to see what functions the program is most busy with, and might allow you to see what parts should be optimized.

This is more of a note to myself, but if you're on WSL2 and want to use cargo flamegraph you can use the following command where you likely need to change the 5.4.0-126 version number, as well as the -F frequency for how often to make a sample:

PERF=/usr/lib/linux-tools/5.4.0-126-generic/perf flamegraph -F 100000 -- ./target/release/day14b