Advent of Code 2023 in Rust

See the description of the puzzles at https://adventofcode.com/.
Many thanks to Eric Wastl for providing these challenges.

MIT License
Copyright (c) 2024 Gunter Schmidt.
Source Code: https://github.com/GunterSchmidt/advent-of-code-rust

Goal

Advent of Code Solutions written in Rust with emphasis on performance aspects.

Puzzle data files

As of the Advent of Code rules, the puzzle inputs are not part of this repository.

Under each year a /res folder needs to be presents and the filename should be in the format 'input_day_01.txt'. Otherwise please change the const values in the lib.rs files.

Lessons Learned

Parsing

A lot of puzzles require very small amounts of time to solve. More than half of the time is spent to parse the data. Using input.as_bytes() greatly improves speed as all puzzle inputs are in ASCII.

Minimizing Memory Usage

Generally as few data as possible should be read into the memory.

• If each line/set can be evaluated separately then only that data should be taken from the stream.
• Avoiding to import the data into vectors or the like and instead working with the input data directly can be very beneficial.

Numbers

Interesting enough, 32-Bit calculations can be faster than 64-bit calculations, even on 64-bit systems.

Small vectors

Small vectors can be handled on the stack with crate SmallVec. The amount of time saved can be 30-50%. Arrays are an alternative, too.