Day 154, part 2
This commit is contained in:
Zoé Cassiopée Gauthier
parent
30b20a0a51
commit
fd608ac482
159
src/day15.rs
159
src/day15.rs
@ -1,84 +1,120 @@
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use std::collections::HashSet;
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use std::cmp::Ordering;
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use std::collections::BinaryHeap;
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#[derive(Clone)]
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#[derive(Copy, Clone, Eq, PartialEq)]
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struct Vertex {
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position: (u32, u32),
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position: (usize, usize),
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risk: u32,
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}
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fn remove_min(v: &mut Vec<Vertex>) -> Option<Vertex> {
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let index = v
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.iter()
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.enumerate()
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.min_by(|(_, x), (_, y)| x.risk.cmp(&y.risk))
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.map(|(index, _)| index);
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index.map(|index| v.swap_remove(index))
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impl Ord for Vertex {
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fn cmp(&self, other: &Self) -> Ordering {
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other
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.risk
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.cmp(&self.risk)
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.then_with(|| self.position.cmp(&other.position))
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}
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}
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impl PartialOrd for Vertex {
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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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struct RiskMap {
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levels: Vec<Vec<u32>>,
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target: (u32, u32),
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explored: HashSet<(u32, u32)>,
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size: usize,
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target: (usize, usize),
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risks: Vec<u32>,
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}
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impl RiskMap {
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fn new(levels: Vec<Vec<u32>>) -> RiskMap {
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let target = (levels[0].len() as u32 - 1, levels.len() as u32 - 1);
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let size = levels.len();
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RiskMap {
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levels,
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target,
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explored: HashSet::new(),
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size,
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target: (size - 1, size - 1),
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risks: (0..size * size).map(|_| u32::MAX).collect(),
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}
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}
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fn explore(&mut self, origin: &Vertex, x: i32, y: i32) -> Option<Vertex> {
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if x < 0 || y < 0 || x as u32 > self.target.0 || y as u32 > self.target.1 {
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return None;
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fn explore(&mut self, position: (usize, usize), risk: u32) -> Option<Vertex> {
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let next_risk = risk + self.levels[position.1][position.0];
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if next_risk < self.risks[position.1 * self.size + position.0] {
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self.risks[position.1 * self.size + position.0] = next_risk;
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Some(Vertex {
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position,
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risk: next_risk,
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})
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} else {
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None
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}
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let position = (x as u32, y as u32);
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if self.explored.contains(&position) {
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return None;
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}
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let risk = origin.risk + self.levels[y as usize][x as usize];
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Some(Vertex { position, risk })
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}
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fn shortest_path(&mut self) -> Option<u32> {
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let mut paths: Vec<Vertex> = Vec::new();
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let mut paths: BinaryHeap<Vertex> = BinaryHeap::new();
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paths.push(Vertex {
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position: (0, 0),
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risk: 0,
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});
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loop {
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match remove_min(&mut paths) {
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Some(path) => {
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if path.position == self.target {
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return Some(path.risk);
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}
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self.explored.insert(path.position);
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let (x, y) = (path.position.0 as i32, path.position.1 as i32);
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if let Some(neighbor) = self.explore(&path, x - 1, y) {
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paths.push(neighbor);
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}
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if let Some(neighbor) = self.explore(&path, x + 1, y) {
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paths.push(neighbor);
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}
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if let Some(neighbor) = self.explore(&path, x, y - 1) {
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paths.push(neighbor);
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}
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if let Some(neighbor) = self.explore(&path, x, y + 1) {
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paths.push(neighbor);
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}
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while let Some(Vertex { position, risk }) = paths.pop() {
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if position == self.target {
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return Some(risk);
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}
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if risk > self.risks[position.1 * self.size + position.0] {
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continue;
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}
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if position.0 > 0 {
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if let Some(next) = self.explore((position.0 - 1, position.1), risk) {
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paths.push(next);
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}
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}
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if position.0 < self.size - 1 {
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if let Some(next) = self.explore((position.0 + 1, position.1), risk) {
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paths.push(next);
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}
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}
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if position.1 > 0 {
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if let Some(next) = self.explore((position.0, position.1 - 1), risk) {
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paths.push(next);
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}
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}
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if position.1 < self.size - 1 {
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if let Some(next) = self.explore((position.0, position.1 + 1), risk) {
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paths.push(next);
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}
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None => return None,
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}
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}
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None
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}
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}
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fn expand_map(risk_map: Vec<Vec<u32>>) -> Vec<Vec<u32>> {
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let mut result = Vec::new();
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for i in 0..5 {
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for row in risk_map.iter() {
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let rows = [
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row.iter()
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.map(|x| (x + i - 1) % 9 + 1)
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.collect::<Vec<u32>>(),
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row.iter().map(|x| (x + i) % 9 + 1).collect(),
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row.iter().map(|x| (x + i + 1) % 9 + 1).collect(),
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row.iter().map(|x| (x + i + 2) % 9 + 1).collect(),
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row.iter().map(|x| (x + i + 3) % 9 + 1).collect(),
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];
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result.push(rows.concat());
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}
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}
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result
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}
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fn main() {
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const INPUT: &str = include_str!("../inputs/day15.txt");
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let risk_level = INPUT
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@ -87,6 +123,13 @@ fn main() {
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.collect::<Vec<Vec<u32>>>();
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let mut risk_map = RiskMap::new(risk_level);
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println!("solution {}", risk_map.shortest_path().unwrap());
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let risk_level = INPUT
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.lines()
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.map(|line| line.chars().map(|c| c.to_digit(10).unwrap()).collect())
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.collect::<Vec<Vec<u32>>>();
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let mut risk_map = RiskMap::new(expand_map(risk_level));
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println!("solution {}", risk_map.shortest_path().unwrap());
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}
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#[test]
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@ -108,3 +151,23 @@ fn test_shortest_path() {
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let mut risk_map = RiskMap::new(risk_level);
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assert_eq!(risk_map.shortest_path().unwrap(), 40);
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}
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#[test]
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fn test_expand_map() {
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const INPUT: &str = "1163751742
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1381373672
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2136511328
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3694931569
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7463417111
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1319128137
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1359912421
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3125421639
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1293138521
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2311944581";
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let risk_level = INPUT
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.lines()
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.map(|line| line.chars().map(|c| c.to_digit(10).unwrap()).collect())
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.collect::<Vec<Vec<u32>>>();
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let mut risk_map = RiskMap::new(expand_map(risk_level));
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assert_eq!(risk_map.shortest_path().unwrap(), 315);
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}
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