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BakerNetBakerNet
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Day 16
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‎.cargo/config.toml

+1-1
Original file line numberDiff line numberDiff line change
@@ -5,4 +5,4 @@ read = "run --quiet --release -- read"
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solve = "run --quiet --release -- solve"
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all = "run --quiet --release -- all"
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time = "run --quiet --release -- all --release --time"
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time = "run --quiet --release -- time"

‎aoc2024/data/examples/16-2.txt

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@@ -0,0 +1,17 @@
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#################
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#...#...#...#..E#
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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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#.#.#...#.....#.#
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#.#.#.#####.###.#
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#.#.#.........#.#
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#.#.#.#########.#
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#S#.............#
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#################

‎aoc2024/data/examples/16.txt

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@@ -0,0 +1,15 @@
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###############
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#.......#....E#
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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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#.....#...#.#.#
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#.###.#.#.#.#.#
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#S..#.....#...#
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###############

‎aoc2024/src/bin/16.rs

+252
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,252 @@
1+
use std::{
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cmp::Ordering,
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collections::{BinaryHeap, HashMap, HashSet},
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};
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use aoc_utils::*;
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advent_of_code::solution!(16);
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#[derive(Clone, Eq, PartialEq)]
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struct State {
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cost: usize,
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position: Point,
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direction: Dir,
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}
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impl Ord for State {
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fn cmp(&self, other: &Self) -> Ordering {
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other.cost.cmp(&self.cost)
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}
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}
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impl PartialOrd for State {
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fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
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Some(self.cmp(other))
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}
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}
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fn dijkstra(map: &[Vec<char>], start: Point, goal: Point) -> Option<u64> {
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let mut dist: HashMap<(Point, Dir), usize> = HashMap::new();
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let mut heap = BinaryHeap::new();
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let bounds = Bounds(map.len() - 1, map[0].len() - 1);
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heap.push(State {
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cost: 0,
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position: start,
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direction: Dir::Right, // dummy value
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});
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while let Some(State {
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cost,
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position,
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direction,
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}) = heap.pop()
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{
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if position == goal {
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return Some(cost as u64);
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}
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if let Some(found) = dist.get(&(position, direction)) {
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if *found < cost {
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continue;
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}
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}
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if let Some(next) = direction.next(position, bounds) {
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if map[next.0][next.1] != '#' {
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heap.push(State {
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cost: cost + 1,
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position: next,
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direction,
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});
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}
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}
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for new_dir in vec![direction.cw(), direction.ccw()].into_iter() {
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let np = new_dir
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.next(position, bounds)
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.expect("np should always be valid due to wall");
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if map[np.0][np.1] == '#' {
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continue;
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}
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let next = State {
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cost: cost + 1000,
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position,
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direction: new_dir,
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};
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let new_cost = next.cost;
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if let Some(found) = dist.get(&(position, new_dir)) {
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if new_cost < *found {
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heap.push(next);
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dist.insert((position, new_dir), new_cost);
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}
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} else {
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heap.push(next);
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dist.insert((position, new_dir), new_cost);
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}
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}
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}
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None
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}
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#[derive(Clone, Eq, PartialEq)]
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struct StateP2 {
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cost: usize,
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position: Point,
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direction: Dir,
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path: Vec<Point>,
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}
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impl Ord for StateP2 {
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fn cmp(&self, other: &Self) -> Ordering {
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other.cost.cmp(&self.cost)
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}
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}
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impl PartialOrd for StateP2 {
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fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
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Some(self.cmp(other))
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}
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}
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fn dijkstra_part2(map: &[Vec<char>], start: Point, goal: Point) -> Option<u64> {
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let mut dist: HashMap<(Point, Dir), usize> = HashMap::new();
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let mut heap = BinaryHeap::new();
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let bounds = Bounds(map.len() - 1, map[0].len() - 1);
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heap.push(StateP2 {
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cost: 0,
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position: start,
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direction: Dir::Right, // dummy value
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path: vec![start],
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});
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let mut res = None::<u64>;
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let mut best: HashSet<Point> = HashSet::new();
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while let Some(StateP2 {
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cost,
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position,
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direction,
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path,
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}) = heap.pop()
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{
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if position == goal {
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if let Some(c) = res {
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if cost as u64 > c {
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return Some(best.len() as u64);
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} else {
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path.into_iter().for_each(|p| {
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best.insert(p);
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});
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continue;
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}
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} else {
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res = Some(cost as u64);
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path.into_iter().for_each(|p| {
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best.insert(p);
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});
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continue;
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}
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}
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if let Some(found) = dist.get(&(position, direction)) {
160+
if *found < cost {
161+
continue;
162+
}
163+
}
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if let Some(next) = direction.next(position, bounds) {
166+
if map[next.0][next.1] != '#' {
167+
let mut new_path = path.clone();
168+
new_path.push(next);
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heap.push(StateP2 {
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cost: cost + 1,
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position: next,
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direction,
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path: new_path,
174+
});
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}
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}
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for new_dir in vec![direction.cw(), direction.ccw()].into_iter() {
179+
let np = new_dir
180+
.next(position, bounds)
181+
.expect("np should always be valid due to wall");
182+
if map[np.0][np.1] == '#' {
183+
continue;
184+
}
185+
let next = StateP2 {
186+
cost: cost + 1000,
187+
position,
188+
direction: new_dir,
189+
path: path.clone(),
190+
};
191+
let new_cost = next.cost;
192+
193+
if let Some(found) = dist.get(&(position, new_dir)) {
194+
if new_cost <= *found {
195+
heap.push(next);
196+
dist.insert((position, new_dir), new_cost);
197+
}
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} else {
199+
heap.push(next);
200+
dist.insert((position, new_dir), new_cost);
201+
}
202+
}
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}
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None
205+
}
206+
207+
pub fn part_one(input: &str) -> Option<u64> {
208+
let map = input.c_map();
209+
let start = find_point(&map, 'S');
210+
let end = find_point(&map, 'E');
211+
dijkstra(&map, start, end)
212+
}
213+
214+
pub fn part_two(input: &str) -> Option<u64> {
215+
let map = input.c_map();
216+
let start = find_point(&map, 'S');
217+
let end = find_point(&map, 'E');
218+
dijkstra_part2(&map, start, end)
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}
220+
221+
#[cfg(test)]
222+
mod tests {
223+
use super::*;
224+
225+
#[test]
226+
fn test_part_one() {
227+
let result = part_one(&advent_of_code::template::read_file("examples", DAY));
228+
assert_eq!(result, Some(7036));
229+
}
230+
231+
#[test]
232+
fn test_part_one_two() {
233+
let result = part_one(&advent_of_code::template::read_file_part(
234+
"examples", DAY, 2,
235+
));
236+
assert_eq!(result, Some(11048));
237+
}
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#[test]
240+
fn test_part_two() {
241+
let result = part_two(&advent_of_code::template::read_file("examples", DAY));
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assert_eq!(result, Some(45));
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}
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#[test]
246+
fn test_part_two_two() {
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let result = part_two(&advent_of_code::template::read_file_part(
248+
"examples", DAY, 2,
249+
));
250+
assert_eq!(result, Some(64));
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}
252+
}

‎aoc_utils/src/lib.rs

+25-6
Original file line numberDiff line numberDiff line change
@@ -4,15 +4,34 @@ use itertools::Itertools;
44
use regex::{Captures, Regex};
55
use tinyvec::{ArrayVec, array_vec};
66

7-
#[derive(Debug, Default, Clone, Copy, PartialEq, Eq)]
8-
pub struct Point(usize, usize);
9-
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
10-
pub struct Bounds(usize, usize);
7+
#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, PartialOrd, Hash)]
8+
pub struct Point(pub usize, pub usize);
119

12-
#[derive(Debug, Default, Clone, Copy, PartialEq, Eq)]
13-
pub struct IPoint(i64, i64);
10+
pub fn find_point<U>(map: &[Vec<U>], val: U) -> Point
11+
where
12+
U: PartialEq,
13+
{
14+
map.iter()
15+
.enumerate()
16+
.find_map(|(row, v)| {
17+
v.iter().enumerate().find_map(|(col, item)| {
18+
if *item == val {
19+
Some(Point(row, col))
20+
} else {
21+
None
22+
}
23+
})
24+
})
25+
.expect("Should find point")
26+
}
1427

1528
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
29+
pub struct Bounds(pub usize, pub usize);
30+
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#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, PartialOrd, Hash)]
32+
pub struct IPoint(pub i64, pub i64);
33+
34+
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1635
pub enum Dir {
1736
Up,
1837
Down,

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