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‎2024/README.md

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# Advent of Code in Rust 🦀
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![AoC2024](https://img.shields.io/badge/Advent_of_Code-2024-8A2BE2)
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![Stars: 10](https://img.shields.io/badge/Stars-10⭐-blue)
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![Rust: 5](https://img.shields.io/badge/Rust-5-cyan?logo=Rust)
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![Stars: 12](https://img.shields.io/badge/Stars-12⭐-blue)
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![Rust: 6](https://img.shields.io/badge/Rust-6-cyan?logo=Rust)
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![Python: 4](https://img.shields.io/badge/Python-4-cyan?logo=Python)
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## 2024 ([Calendar](https://adventofcode.com/2024)) ([Solutions](../2024/)) : 10⭐
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## 2024 ([Calendar](https://adventofcode.com/2024)) ([Solutions](../2024/)) : 12⭐
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Puzzle | Stars | Languages
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---------------------------------------------------------------- | ----- | -----------
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[Day 3: Mull It Over](https://adventofcode.com/2024/day/3) | ⭐⭐ | [![Rust](../scripts/assets/rust.png)](../2024/day3/day3.rs) [![Python](../scripts/assets/python.png)](../2024/day3/day3.py) [![Go](../scripts/assets/go.png)](../2024/day3/day3.go) [![Perl](../scripts/assets/perl.png)](../2024/day3/day3.pl)
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[Day 4: Ceres Search](https://adventofcode.com/2024/day/4) | ⭐⭐ | [![Rust](../scripts/assets/rust.png)](../2024/day4/day4.rs) [![Python](../scripts/assets/python.png)](../2024/day4/day4.py)
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[Day 5: Print Queue](https://adventofcode.com/2024/day/5) | ⭐⭐ | [![Rust](../scripts/assets/rust.png)](../2024/day5/day5.rs)
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[Day 6: Guard Gallivant](https://adventofcode.com/2024/day/6) | ⭐⭐ | [![Rust](../scripts/assets/rust.png)](../2024/day6/day6.rs)

‎2024/day6/Cargo.toml

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[package]
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name = "day6"
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version = "0.1.0"
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edition = "2021"
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[dependencies]
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aoc = { path = "../../aoc" }
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[[bin]]
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name = "day6"
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path = "day6.rs"

‎2024/day6/day6.rs

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//! [Day 6: Guard Gallivant](https://adventofcode.com/2024/day/6)
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use aoc::{grid, grid::Direction, grid::Grid};
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use std::collections::HashSet;
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struct Puzzle {
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grid: Grid<char>,
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start: (usize, usize),
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}
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impl Puzzle {
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fn new() -> Puzzle {
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Puzzle {
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grid: grid![],
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start: (0, 0),
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}
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}
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/// Get the puzzle input.
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fn configure(&mut self, path: &str) {
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let data = std::fs::read_to_string(path).unwrap();
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self.grid = aoc::grid::Grid::<char>::parse(&data);
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for (x, y, p) in self.grid.iter() {
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if p == &'^' {
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self.start = (x, y);
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break;
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}
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}
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}
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fn move_guard(
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&self,
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x: &mut usize,
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y: &mut usize,
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direction: &mut grid::Direction,
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obstruction: (usize, usize),
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) -> bool {
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match direction {
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Direction::East => {
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if *x == 0 {
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return true;
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} else if self.grid[(*x - 1, *y)] == '#' || (*x - 1, *y) == obstruction {
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*direction = Direction::North;
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} else {
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*x -= 1;
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}
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}
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Direction::West => {
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if *x == self.grid.size().0 - 1 {
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return true;
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} else if self.grid[(*x + 1, *y)] == '#' || (*x + 1, *y) == obstruction {
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*direction = Direction::South;
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} else {
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*x += 1;
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}
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}
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Direction::North => {
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if *y == 0 {
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return true;
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} else if self.grid[(*x, *y - 1)] == '#' || (*x, *y - 1) == obstruction {
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*direction = Direction::West;
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} else {
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*y -= 1;
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}
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}
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Direction::South => {
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if *y == self.grid.size().1 - 1 {
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return true;
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} else if self.grid[(*x, *y + 1)] == '#' || (*x, *y + 1) == obstruction {
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*direction = Direction::East;
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} else {
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*y += 1;
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}
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}
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};
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false
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}
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/// Solve part one.
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fn part1(&self) -> usize {
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let (mut x, mut y) = self.start;
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let mut direction = grid::Direction::North;
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let mut leave = false;
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let mut seen = HashSet::new();
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let obstruction = (usize::MAX, usize::MAX);
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while !leave {
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seen.insert((x, y));
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leave = self.move_guard(&mut x, &mut y, &mut direction, obstruction);
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}
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seen.len()
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}
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/// Solve part two.
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fn part2(&self) -> u32 {
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// repeat part 1 to eliminate positions that are never visited
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let (mut x, mut y) = self.start;
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let mut direction = grid::Direction::North;
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let mut leave = false;
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let obstruction = (usize::MAX, usize::MAX);
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let mut normal_walk = HashSet::new();
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while !leave {
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normal_walk.insert((x, y));
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leave = self.move_guard(&mut x, &mut y, &mut direction, obstruction);
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}
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let mut stuck = 0;
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for (ox, oy, c) in self.grid.iter() {
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// optimization: if the guard never walks to this position,
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// an obstruction cannot deviate him
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if !normal_walk.contains(&(ox, oy)) {
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continue;
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}
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if c == &'.' {
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// can choose this position for the obstruction
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let obstruction = (ox, oy);
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let (mut x, mut y) = self.start;
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let mut direction = grid::Direction::North;
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let mut leave = false;
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let mut seen: HashSet<(usize, usize, Direction)> = HashSet::new();
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while !leave {
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if seen.contains(&(x, y, direction)) {
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// same pos, same direction : the guard is stuck
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stuck += 1;
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break;
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}
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seen.insert((x, y, direction));
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leave = self.move_guard(&mut x, &mut y, &mut direction, obstruction);
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}
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}
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}
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stuck
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}
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}
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fn main() {
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let args = aoc::parse_args();
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let mut puzzle = Puzzle::new();
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puzzle.configure(args.path.as_str());
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println!("{}", puzzle.part1());
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println!("{}", puzzle.part2());
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}
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/// Test from puzzle input
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#[cfg(test)]
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mod test {
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use super::*;
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#[test]
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fn test01() {
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let mut puzzle = Puzzle::new();
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puzzle.configure("test.txt");
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assert_eq!(puzzle.part1(), 41);
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}
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#[test]
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fn test02() {
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let mut puzzle = Puzzle::new();
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puzzle.configure("test.txt");
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assert_eq!(puzzle.part2(), 6);
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}
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}

‎2024/day6/test.txt

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....#.....
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.........#
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..........
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..#.......
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.......#..
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..........
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.#..^.....
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........#.
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#.........
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......#...

‎README.md

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# Advent of Code in Rust 🦀
22

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![Stars: 460](https://img.shields.io/badge/Stars-460⭐-blue)
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![Rust: 176](https://img.shields.io/badge/Rust-176-cyan?logo=Rust)
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![Stars: 462](https://img.shields.io/badge/Stars-462⭐-blue)
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![Rust: 177](https://img.shields.io/badge/Rust-177-cyan?logo=Rust)
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![Python: 117](https://img.shields.io/badge/Python-117-cyan?logo=Python)
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Solutions of [Advent of Code](https://adventofcode.com/) in [Rust](https://www.rust-lang.org), and sometimes in [Python](https://www.python.org/).
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Made for fun 😎 and to practice Rust. Many thanks to [Eric Wastl](https://twitter.com/ericwastl).
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## 2024 (current event) ([Calendar](https://adventofcode.com/2024)) ([Solutions](2024/)) : 10⭐
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## 2024 (current event) ([Calendar](https://adventofcode.com/2024)) ([Solutions](2024/)) : 12⭐
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Puzzle | Stars | Languages
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---------------------------------------------------------------- | ----- | -----------
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[Day 3: Mull It Over](https://adventofcode.com/2024/day/3) | ⭐⭐ | [![Rust](./scripts/assets/rust.png)](./2024/day3/day3.rs) [![Python](./scripts/assets/python.png)](./2024/day3/day3.py) [![Go](./scripts/assets/go.png)](./2024/day3/day3.go) [![Perl](./scripts/assets/perl.png)](./2024/day3/day3.pl)
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[Day 4: Ceres Search](https://adventofcode.com/2024/day/4) | ⭐⭐ | [![Rust](./scripts/assets/rust.png)](./2024/day4/day4.rs) [![Python](./scripts/assets/python.png)](./2024/day4/day4.py)
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[Day 5: Print Queue](https://adventofcode.com/2024/day/5) | ⭐⭐ | [![Rust](./scripts/assets/rust.png)](./2024/day5/day5.rs)
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[Day 6: Guard Gallivant](https://adventofcode.com/2024/day/6) | ⭐⭐ | [![Rust](./scripts/assets/rust.png)](./2024/day6/day6.rs)
2021

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## Paste years
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Calendar | Solutions | Stars | Rust | Python
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-------- | --------- | ----- | ---- | ------
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[Advent of Code 2024](https://adventofcode.com/2024) | [Solutions](2024/README.md) | 10⭐ | 5 | 4
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[Advent of Code 2024](https://adventofcode.com/2024) | [Solutions](2024/README.md) | 12⭐ | 6 | 4
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[Advent of Code 2023](https://adventofcode.com/2023) | [Solutions](2023/README.md) | 50⭐ | 24 | 11
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[Advent of Code 2022](https://adventofcode.com/2022) | [Solutions](2022/README.md) | 50⭐ | 24 | 18
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[Advent of Code 2021](https://adventofcode.com/2021) | [Solutions](2021/README.md) | 50⭐ | 23 | 12

‎aoc/src/grid.rs

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];
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/// The four directions
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#[derive(PartialEq, Clone, Copy, Eq, Debug)]
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#[derive(PartialEq, Clone, Copy, Eq, Hash, Debug)]
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pub enum Direction {
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North,
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East,

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