day-16 done and dusted
This commit is contained in:
Dylan Thies
4
2023/day-16/src/lib.rs
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4
2023/day-16/src/lib.rs
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pub mod part1;
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pub use crate::part1::*;
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pub mod part2;
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pub use crate::part2::*;
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12
2023/day-16/src/main.rs
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12
2023/day-16/src/main.rs
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#![warn(clippy::all, clippy::pedantic)]
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use day_16::part1;
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use day_16::part2;
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fn main() {
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let input = include_str!("./input.txt");
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let part1_result = part1(input);
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println!("part 1: {part1_result}");
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let part2_result = part2(input);
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println!("part 2: {part2_result}");
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}
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162
2023/day-16/src/part1.rs
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162
2023/day-16/src/part1.rs
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@@ -0,0 +1,162 @@
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#![warn(clippy::all, clippy::pedantic)]
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use std::collections::{HashMap, HashSet, VecDeque};
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use glam::IVec2;
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use nom::{
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branch::alt,
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bytes::complete::tag,
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character::complete,
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combinator::eof,
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multi::{fold_many1, many1},
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sequence::terminated,
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IResult, Parser,
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};
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use nom_locate::LocatedSpan;
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type Span<'a> = LocatedSpan<&'a str>;
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type SpanIVec2<'a> = LocatedSpan<&'a str, IVec2>;
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#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
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enum Gadget {
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Horizontal,
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Vertical,
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UlDr,
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UrDl,
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None,
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}
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#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
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enum FromDir {
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Left,
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Right,
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Up,
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Down,
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}
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/// day 16 part 1 of aoc 2023
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///
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/// # Arguments
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/// - input the input for today's puzzle
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///
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/// # Panics
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/// panics whne it cannot parse the input OR when ever the number of game numbers is greater than
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#[must_use]
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pub fn part1(input: &str) -> String {
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let input = Span::new(input);
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let (_, (gadgets, maxes)) = parse_input(input).expect("always aoc");
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let mut movement_cache = HashSet::new();
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let mut visited = HashSet::new();
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let mut queue = VecDeque::from([(IVec2::new(0, 0), FromDir::Left)]);
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while !queue.is_empty() {
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let pos = queue.pop_front().unwrap();
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if !movement_cache.insert(pos) {
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continue; // cycle detection
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}
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let (pos, from) = pos;
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if pos.x >= maxes.x || pos.x < 0 || pos.y >= maxes.y || pos.y < 0 {
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continue; //outside grid
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}
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visited.insert(pos);
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if let Some(gadget) = gadgets.get(&pos) {
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match (gadget, from) {
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(Gadget::Horizontal, FromDir::Left) => {
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queue.push_back((pos + IVec2::new(1, 0), from));
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}
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(Gadget::Horizontal, FromDir::Right) => {
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queue.push_back((pos + IVec2::new(-1, 0), from));
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}
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(Gadget::Horizontal, FromDir::Up | FromDir::Down) => {
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queue.push_back((pos + IVec2::new(1, 0), FromDir::Left));
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queue.push_back((pos + IVec2::new(-1, 0), FromDir::Right));
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}
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(Gadget::Vertical, FromDir::Up) => queue.push_back((pos + IVec2::new(0, 1), from)),
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(Gadget::Vertical, FromDir::Down) => {
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queue.push_back((pos + IVec2::new(0, -1), from));
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}
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(Gadget::Vertical, FromDir::Left | FromDir::Right) => {
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queue.push_back((pos + IVec2::new(0, 1), FromDir::Up));
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queue.push_back((pos + IVec2::new(0, -1), FromDir::Down));
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}
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(Gadget::UlDr, FromDir::Up) | (Gadget::UrDl, FromDir::Down) => {
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queue.push_back((pos + IVec2::new(1, 0), FromDir::Left));
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}
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(Gadget::UlDr, FromDir::Down) | (Gadget::UrDl, FromDir::Up) => {
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queue.push_back((pos + IVec2::new(-1, 0), FromDir::Right));
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}
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(Gadget::UlDr, FromDir::Left) | (Gadget::UrDl, FromDir::Right) => {
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queue.push_back((pos + IVec2::new(0, 1), FromDir::Up));
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}
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(Gadget::UlDr, FromDir::Right) | (Gadget::UrDl, FromDir::Left) => {
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queue.push_back((pos + IVec2::new(0, -1), FromDir::Down));
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}
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_ => unimplemented!("This should never happen"),
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};
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} else {
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let next_pos = pos
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+ match from {
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FromDir::Left => IVec2::new(1, 0),
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FromDir::Right => IVec2::new(-1, 0),
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FromDir::Up => IVec2::new(0, 1),
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FromDir::Down => IVec2::new(0, -1),
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};
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queue.push_back((next_pos, from));
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}
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}
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visited.len().to_string()
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}
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fn with_xy(span: Span) -> SpanIVec2 {
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let x = i32::try_from(span.get_column()).expect("overflow") - 1;
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let y = i32::try_from(span.location_line()).expect("wrap around") - 1;
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span.map_extra(|()| IVec2::new(x, y))
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}
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fn parse_gadget(input: Span) -> IResult<Span, (IVec2, Gadget)> {
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alt((
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tag("-").map(with_xy).map(|x| (x.extra, Gadget::Horizontal)),
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tag("|").map(with_xy).map(|x| (x.extra, Gadget::Vertical)),
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tag(r"\").map(with_xy).map(|x| (x.extra, Gadget::UlDr)),
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tag(r"/").map(with_xy).map(|x| (x.extra, Gadget::UrDl)),
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tag(".").map(with_xy).map(|x| (x.extra, Gadget::None)),
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))(input)
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}
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fn parse_input(input: Span) -> IResult<Span, (HashMap<IVec2, Gadget>, IVec2)> {
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let (input, (gadgets, max_x, max_y)) = fold_many1(
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terminated(many1(parse_gadget), alt((complete::line_ending, eof))),
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|| (HashMap::new(), 0, 0),
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|(mut acc, _, max_y), row| {
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let max_x = row.len().try_into().unwrap();
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row.into_iter()
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.filter(|(_, gadget)| *gadget != Gadget::None)
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.for_each(|(pos, gadget)| {
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acc.insert(pos, gadget);
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});
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(acc, max_x, max_y + 1)
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},
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)(input)?;
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Ok((input, (gadgets, IVec2::new(max_x, max_y))))
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}
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#[cfg(test)]
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mod test {
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use super::*;
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const INPUT: &str = r".|...\....
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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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#[test]
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fn part1_works() {
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let result = part1(INPUT);
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assert_eq!(result, "46".to_string());
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}
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}
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187
2023/day-16/src/part2.rs
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187
2023/day-16/src/part2.rs
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@@ -0,0 +1,187 @@
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#![warn(clippy::all, clippy::pedantic)]
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use std::collections::{HashMap, HashSet, VecDeque};
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use glam::IVec2;
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use nom::{
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branch::alt,
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bytes::complete::tag,
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character::complete,
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combinator::eof,
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multi::{fold_many1, many1},
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sequence::terminated,
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IResult, Parser,
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};
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use nom_locate::LocatedSpan;
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type Span<'a> = LocatedSpan<&'a str>;
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type SpanIVec2<'a> = LocatedSpan<&'a str, IVec2>;
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#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
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enum Gadget {
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Horizontal,
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Vertical,
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UlDr,
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UrDl,
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None,
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}
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#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
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enum FromDir {
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Left,
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Right,
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Up,
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Down,
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}
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/// day 16 part 2 of aoc 2023
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///
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/// # Arguments
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/// - input the input for today's puzzle
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///
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/// # Panics
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/// panics whne it cannot parse the input OR when ever the number of game numbers is greater than
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#[must_use]
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pub fn part2(input: &str) -> String {
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let input = Span::new(input);
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let (_, (gadgets, maxes)) = parse_input(input).expect("always aoc");
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(0..maxes.x)
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.flat_map(|x| {
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[
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(IVec2::new(x, 0), FromDir::Up),
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(IVec2::new(x, maxes.y - 1), FromDir::Down),
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]
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})
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.chain((0..maxes.y).flat_map(|y| {
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[
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(IVec2::new(0, y), FromDir::Left),
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(IVec2::new(maxes.x - 1, y), FromDir::Right),
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]
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}))
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.map(|(start_pos, from)| check_from_start(start_pos, from, &gadgets, maxes))
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.max()
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.unwrap()
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.to_string()
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}
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fn check_from_start(
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start_pos: IVec2,
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from: FromDir,
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gadgets: &HashMap<IVec2, Gadget>,
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maxes: IVec2,
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) -> usize {
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let mut movement_cache = HashSet::new();
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let mut visited = HashSet::new();
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let mut queue = VecDeque::from([(start_pos, from)]);
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while !queue.is_empty() {
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let pos = queue.pop_front().unwrap();
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if !movement_cache.insert(pos) {
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continue; // cycle detection
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}
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let (pos, from) = pos;
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if pos.x >= maxes.x || pos.x < 0 || pos.y >= maxes.y || pos.y < 0 {
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continue; //outside grid
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}
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visited.insert(pos);
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if let Some(gadget) = gadgets.get(&pos) {
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match (gadget, from) {
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(Gadget::Horizontal, FromDir::Left) => {
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queue.push_back((pos + IVec2::new(1, 0), from));
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}
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(Gadget::Horizontal, FromDir::Right) => {
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queue.push_back((pos + IVec2::new(-1, 0), from));
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}
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(Gadget::Horizontal, FromDir::Up | FromDir::Down) => {
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queue.push_back((pos + IVec2::new(1, 0), FromDir::Left));
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queue.push_back((pos + IVec2::new(-1, 0), FromDir::Right));
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}
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(Gadget::Vertical, FromDir::Up) => queue.push_back((pos + IVec2::new(0, 1), from)),
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(Gadget::Vertical, FromDir::Down) => {
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queue.push_back((pos + IVec2::new(0, -1), from));
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}
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(Gadget::Vertical, FromDir::Left | FromDir::Right) => {
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queue.push_back((pos + IVec2::new(0, 1), FromDir::Up));
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queue.push_back((pos + IVec2::new(0, -1), FromDir::Down));
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}
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(Gadget::UlDr, FromDir::Up) | (Gadget::UrDl, FromDir::Down) => {
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queue.push_back((pos + IVec2::new(1, 0), FromDir::Left));
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}
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(Gadget::UlDr, FromDir::Down) | (Gadget::UrDl, FromDir::Up) => {
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queue.push_back((pos + IVec2::new(-1, 0), FromDir::Right));
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}
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(Gadget::UlDr, FromDir::Left) | (Gadget::UrDl, FromDir::Right) => {
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queue.push_back((pos + IVec2::new(0, 1), FromDir::Up));
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}
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(Gadget::UlDr, FromDir::Right) | (Gadget::UrDl, FromDir::Left) => {
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queue.push_back((pos + IVec2::new(0, -1), FromDir::Down));
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}
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_ => unimplemented!("This should never happen"),
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};
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} else {
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let next_pos = pos
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+ match from {
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FromDir::Left => IVec2::new(1, 0),
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FromDir::Right => IVec2::new(-1, 0),
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FromDir::Up => IVec2::new(0, 1),
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FromDir::Down => IVec2::new(0, -1),
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};
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queue.push_back((next_pos, from));
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}
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}
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visited.len()
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}
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fn with_xy(span: Span) -> SpanIVec2 {
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let x = i32::try_from(span.get_column()).expect("overflow") - 1;
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let y = i32::try_from(span.location_line()).expect("wrap around") - 1;
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span.map_extra(|()| IVec2::new(x, y))
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}
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fn parse_gadget(input: Span) -> IResult<Span, (IVec2, Gadget)> {
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alt((
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tag("-").map(with_xy).map(|x| (x.extra, Gadget::Horizontal)),
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tag("|").map(with_xy).map(|x| (x.extra, Gadget::Vertical)),
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tag(r"\").map(with_xy).map(|x| (x.extra, Gadget::UlDr)),
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tag(r"/").map(with_xy).map(|x| (x.extra, Gadget::UrDl)),
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tag(".").map(with_xy).map(|x| (x.extra, Gadget::None)),
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))(input)
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}
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fn parse_input(input: Span) -> IResult<Span, (HashMap<IVec2, Gadget>, IVec2)> {
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let (input, (gadgets, max_x, max_y)) = fold_many1(
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terminated(many1(parse_gadget), alt((complete::line_ending, eof))),
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|| (HashMap::new(), 0, 0),
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|(mut acc, _, max_y), row| {
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let max_x = row.len().try_into().unwrap();
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row.into_iter()
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.filter(|(_, gadget)| *gadget != Gadget::None)
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.for_each(|(pos, gadget)| {
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acc.insert(pos, gadget);
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});
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(acc, max_x, max_y + 1)
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},
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)(input)?;
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Ok((input, (gadgets, IVec2::new(max_x, max_y))))
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}
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#[cfg(test)]
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mod test {
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use super::*;
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const INPUT: &str = r".|...\....
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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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#[test]
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fn part2_works() {
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let result = part2(INPUT);
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assert_eq!(result, "51".to_string());
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}
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}
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Reference in New Issue
Block a user