This commit is contained in:
Andrew Glaze 2023-12-27 09:04:34 -05:00
parent b802cf1d16
commit bdc150d0ed
3 changed files with 159 additions and 2 deletions

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@ -47,10 +47,10 @@ fn part2(input: &Vec<String>) -> usize {
if let Some(position) = boxes[box_number].iter().position(|(l, _)| *l == *label) { if let Some(position) = boxes[box_number].iter().position(|(l, _)| *l == *label) {
let _ = std::mem::replace( let _ = std::mem::replace(
&mut boxes[box_number][position], &mut boxes[box_number][position],
(label.clone().to_string(), *focal_length as usize), (label.to_string(), *focal_length as usize),
); );
} else { } else {
boxes[box_number].push((label.clone().to_string(), *focal_length as usize)); boxes[box_number].push((label.to_string(), *focal_length as usize));
} }
} else { } else {
panic!("invalid step AHHH {}", step) panic!("invalid step AHHH {}", step)

156
src/day23.rs Normal file
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@ -0,0 +1,156 @@
use std::collections::HashMap;
use aoc_runner_derive::{aoc, aoc_generator};
const NEIGHBORS: &[(i64,i64)] = &[(-1,0),(0,1),(1,0),(0,-1)];
use itertools::Itertools;
#[aoc_generator(day23)]
fn parse(input: &str) -> Vec<Vec<char>> {
input.lines().map(|x| x.chars().collect::<Vec<_>>()).collect::<Vec<_>>()
}
fn dfs(graph: &HashMap<(usize,usize), Vec<(usize,usize,usize)>>, seen: &mut Vec<Vec<bool>>, (r,c): (usize, usize)) -> Option<usize> {
if r == seen.len() - 1 {
return Some(0);
}
let mut max_dist = None;
for &(rr, cc, d) in &graph[&(r,c)] {
if !seen[rr][cc] {
seen[rr][cc] = true;
if let Some(dist) = dfs(graph, seen, (rr,cc)) {
max_dist = Some(max_dist.unwrap_or(0).max(d+dist))
}
seen[rr][cc] = false;
}
}
max_dist
}
#[aoc(day23, part1)]
fn part1(grid: &Vec<Vec<char>>) -> usize {
let mut graph = HashMap::<_,Vec<_>>::new();
for (r, c) in (0..grid.len()).cartesian_product(0..grid[0].len()) {
let neighbors = match grid[r][c] {
'#' => continue,
'.' => NEIGHBORS,
'^' => &NEIGHBORS[0..][..1],
'>' => &NEIGHBORS[1..][..1],
'v' => &NEIGHBORS[2..][..1],
'<' => &NEIGHBORS[3..][..1],
_ => unreachable!(),
};
let e = graph.entry((r,c)).or_default();
for (dr, dc) in neighbors {
let rr = (r as i64 + dr) as usize;
let cc = (c as i64 + dc) as usize;
if grid.get(rr).and_then(|row| row.get(cc)).is_some_and(|&t| t != '#') {
e.push((rr,cc,1));
}
}
}
let corridors = graph.iter()
.filter(|(_, n)| n.len() == 2)
.map(|(&node, _)| node)
.collect::<Vec<_>>();
for (r,c) in corridors {
let neighbors = graph.remove(&(r,c)).unwrap();
let (r1, c1, d1) = neighbors[0];
let (r2, c2, d2) = neighbors[1];
let n1 = graph.get_mut(&(r1,c1)).unwrap();
if let Some(i) = n1.iter().position(|&(rr,cc,_)| (rr,cc) == (r,c)) {
n1[i] = (r2,c2,d1+d2);
}
let n2 = graph.get_mut(&(r2,c2)).unwrap();
if let Some(i) = n2.iter().position(|&(rr,cc,_)| (rr,cc) == (r,c)) {
n2[i] = (r1,c1,d1+d2);
}
}
dfs(&graph, &mut vec![vec![false; grid[0].len()]; grid.len()], (0,1)).unwrap()
}
#[aoc(day23, part2)]
fn part2(grid: &Vec<Vec<char>>) -> usize {
let mut graph = HashMap::<_,Vec<_>>::new();
for (r, c) in (0..grid.len()).cartesian_product(0..grid[0].len()) {
let neighbors = match grid[r][c] {
'#' => continue,
_ => NEIGHBORS,
};
let e = graph.entry((r,c)).or_default();
for (dr, dc) in neighbors {
let rr = (r as i64 + dr) as usize;
let cc = (c as i64 + dc) as usize;
if grid.get(rr).and_then(|row| row.get(cc)).is_some_and(|&t| t != '#') {
e.push((rr,cc,1));
}
}
}
let corridors = graph.iter()
.filter(|(_, n)| n.len() == 2)
.map(|(&node, _)| node)
.collect::<Vec<_>>();
for (r,c) in corridors {
let neighbors = graph.remove(&(r,c)).unwrap();
let (r1, c1, d1) = neighbors[0];
let (r2, c2, d2) = neighbors[1];
let n1 = graph.get_mut(&(r1,c1)).unwrap();
if let Some(i) = n1.iter().position(|&(rr,cc,_)| (rr,cc) == (r,c)) {
n1[i] = (r2,c2,d1+d2);
}
let n2 = graph.get_mut(&(r2,c2)).unwrap();
if let Some(i) = n2.iter().position(|&(rr,cc,_)| (rr,cc) == (r,c)) {
n2[i] = (r1,c1,d1+d2);
}
}
dfs(&graph, &mut vec![vec![false; grid[0].len()]; grid.len()], (0,1)).unwrap()
}
#[cfg(test)]
mod tests {
use super::*;
const EX: &str = r"#.#####################
#.......#########...###
#######.#########.#.###
###.....#.>.>.###.#.###
###v#####.#v#.###.#.###
###.>...#.#.#.....#...#
###v###.#.#.#########.#
###...#.#.#.......#...#
#####.#.#.#######.#.###
#.....#.#.#.......#...#
#.#####.#.#.#########v#
#.#...#...#...###...>.#
#.#.#v#######v###.###v#
#...#.>.#...>.>.#.###.#
#####v#.#.###v#.#.###.#
#.....#...#...#.#.#...#
#.#########.###.#.#.###
#...###...#...#...#.###
###.###.#.###v#####v###
#...#...#.#.>.>.#.>.###
#.###.###.#.###.#.#v###
#.....###...###...#...#
#####################.#";
#[test]
fn part1_example() {
assert_eq!(part1(&parse(EX)), 94);
}
#[test]
fn part2_example() {
assert_eq!(part2(&parse(EX)), 154);
}
}

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@ -1,3 +1,4 @@
mod day23;
mod day22; mod day22;
mod day21; mod day21;
mod day20; mod day20;