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Add 2024 day08 solution
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‎2024/day08/README.md

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# Day 08 - Resonant Collinearity
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> [!NOTE]
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> Input link: <https://adventofcode.com/2024/day/8/input>
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## Part 1
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> [!NOTE]
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> Problem link: <https://adventofcode.com/2024/day/8>
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### Part 1 Solution
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```bash
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$ cargo run --release -- --input 2024/day08/input.txt 2024 08 part1
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295
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```
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## Part 2
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> [!NOTE]
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> Problem link: <https://adventofcode.com/2024/day/8#part2>
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### Part 2 Solution
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```bash
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$ cargo run --release -- --input 2024/day08/input.txt 2024 08 part2
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1034
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```

‎2024/day08/input.txt

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..f........................8......................
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G............8..u.................................
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........G...p.....................................
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......d.....................n.....................
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..................................................
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.....................................K............
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..................F...8.n...B.K...................
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....b.........8..u................................
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...............F.p.......B.............4.....5....
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....f..d..U.........................c.............
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...........U.....d.n.u.0................5.........
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...Y.......f..........................5...........
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..........................u.....d.....e.........4.
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..F...p.............v........n....................
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....s.............0...............................
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...US.s....g.....D..........................4.....
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......wG...............S..........................
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.............................B.....e..............
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.........w.........................A..............
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.............9w.g..........................4......
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U....9..g.....v.....P....D.....f.K................
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.s.............0..9........pP..........5..........
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..9s...................P..........................
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.............b..................0.....A..2....e...
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....................b.....V..v....................
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.......7........B......................A..........
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..................D6...V....q.....................
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...v............D....PV...........................
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.........Y...........g.......................e..y.
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.......SW......V..7....................c..........
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.......bY7.....................N........A.........
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.....................q.N..........y...............
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........................N.........c...............
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..................................................
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.........C..7..................q........2.........
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............................N...q.................
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...W......C3...Q................a1.........y......
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.......W.......................3......2...........
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........3...........6.............1...............
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....3............C.1....................k.........
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E..................................a.....c........
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.............................................w....
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..S.......................Q..........2......k.....
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......................C....6.......Q......ak......
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..................................................
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.................E.............a1............y....
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W..........E......................................
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......E...........6...........Q...................
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...........................k......................
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..................................................

‎2024/day08/input_example.txt

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............
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........0...
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.....0......
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.......0....
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....0.......
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......A.....
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............
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............
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........A...
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.........A..
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............
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............

‎README.md

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@@ -20,3 +20,4 @@ This repository hosts my solutions (and sometimes attempts) for
2020
- Day 05: [Print Queue](./2024/day05/README.md)
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- Day 06: [Guard Gallivant](./2024/day06/README.md)
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- Day 07: [Bridge Repair](./2024/day07/README.md)
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- Day 08: [Resonant Collinearity](./2024/day08/README.md)

‎src/year2024/day08.rs

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use std::collections::{HashMap, HashSet};
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use anyhow::Result;
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use tracing::info;
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#[derive(Debug, clap::Args)]
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pub struct Args {
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#[command(subcommand)]
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pub command: Commands,
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}
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#[derive(Debug, clap::Subcommand)]
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pub enum Commands {
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/// Part 1.
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Part1,
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/// Part 2.
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Part2,
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}
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impl Args {
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pub fn run(self, input: String) -> Result<()> {
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match self.command {
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Commands::Part1 => part1(input),
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Commands::Part2 => part2(input),
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}
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}
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}
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#[derive(Debug, Clone, PartialEq, Eq, Hash)]
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struct Position {
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x: isize,
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y: isize,
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}
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fn part1(input: String) -> Result<()> {
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let width = input.split_once('\n').unwrap().0.len().try_into().unwrap();
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let height = input.lines().count().try_into().unwrap();
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info!("width:{width} height:{height}");
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let antennas: HashMap<String, Vec<Position>> = input
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.lines()
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.enumerate()
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.flat_map(|(y, l)| {
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l.chars().enumerate().filter(|(_, c)| *c != '.').map(move |(x, c)| {
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(
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c.to_string(),
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Position {
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x: x.try_into().unwrap(),
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y: y.try_into().unwrap(),
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},
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)
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})
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})
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.fold(HashMap::new(), |mut acc, (s, p)| {
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acc.entry(s).or_default().push(p);
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acc
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});
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info!("antennas: {antennas:?}");
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let positions: HashSet<Position> = antennas.values().flatten().cloned().collect();
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info!("positions: {positions:?}");
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let mut antinodes = HashSet::new();
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for positions in antennas.values().filter(|p| p.len() > 1) {
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for i in 0..positions.len() {
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let left = &positions[i];
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for right in positions[0..i].iter().chain(&positions[i + 1..]) {
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info!("left:{left:?} right:{right:?}");
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let vector = (right.x - left.x, right.y - left.y);
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let new_pos = Position {
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x: right.x + vector.0,
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y: right.y + vector.1,
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};
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if new_pos.x < 0 || new_pos.x >= width {
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continue;
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}
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if new_pos.y < 0 || new_pos.y >= height {
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continue;
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}
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antinodes.insert(new_pos);
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}
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}
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}
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info!("antinodes: {antinodes:?}");
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println!("{}", antinodes.len());
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Ok(())
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}
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fn part2(input: String) -> Result<()> {
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let width = input.split_once('\n').unwrap().0.len().try_into().unwrap();
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let height = input.lines().count().try_into().unwrap();
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info!("width:{width} height:{height}");
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let antennas: HashMap<String, Vec<Position>> = input
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.lines()
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.enumerate()
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.flat_map(|(y, l)| {
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l.chars().enumerate().filter(|(_, c)| *c != '.').map(move |(x, c)| {
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(
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c.to_string(),
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Position {
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x: x.try_into().unwrap(),
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y: y.try_into().unwrap(),
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},
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)
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})
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})
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.fold(HashMap::new(), |mut acc, (s, p)| {
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acc.entry(s).or_default().push(p);
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acc
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});
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info!("antennas: {antennas:?}");
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let positions: HashSet<Position> = antennas.values().flatten().cloned().collect();
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info!("positions: {positions:?}");
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let mut antinodes = HashSet::new();
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for positions in antennas.values().filter(|p| p.len() > 1) {
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for pos_i in 0..positions.len() {
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let left = &positions[pos_i];
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'positions: for right in positions[0..pos_i].iter().chain(&positions[pos_i + 1..]) {
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antinodes.insert(Position { x: left.x, y: left.y });
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antinodes.insert(Position { x: right.x, y: right.y });
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info!("left:{left:?} right:{right:?}");
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let vector = (right.x - left.x, right.y - left.y);
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for i in 1.. {
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let new_pos = Position {
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x: right.x + vector.0 * i,
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y: right.y + vector.1 * i,
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};
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if new_pos.x < 0 || new_pos.x >= width {
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continue 'positions;
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}
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if new_pos.y < 0 || new_pos.y >= height {
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continue 'positions;
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}
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antinodes.insert(new_pos);
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}
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}
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}
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}
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info!("antinodes: {antinodes:?}");
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println!("{}", antinodes.len());
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Ok(())
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}

‎src/year2024/mod.rs

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mod day05;
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mod day06;
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mod day07;
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mod day08;
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use anyhow::Result;
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/// Advent of Code 2024 - Day 07 - Bridge Repair.
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#[command(visible_aliases = &["day7", "07", "7"])]
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Day07(day07::Args),
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/// Advent of Code 2024 - Day 08 - Resonant Collinearity.
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#[command(visible_aliases = &["day8", "08", "8"])]
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Day08(day08::Args),
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}
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impl Args {
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Commands::Day05(args) => args.run(input),
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Commands::Day06(args) => args.run(input),
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Commands::Day07(args) => args.run(input),
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Commands::Day08(args) => args.run(input),
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}
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}
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}

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