2020: day17: part 1
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parent
8236dbc0c2
commit
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1
Cargo.lock
generated
1
Cargo.lock
generated
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@ -68,6 +68,7 @@ version = "0.1.0"
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dependencies = [
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"anyhow",
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"aoc",
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"itertools",
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]
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[[package]]
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@ -9,6 +9,7 @@ edition = "2018"
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[dependencies]
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aoc = { path = "../aoc" }
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anyhow = "1.0"
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itertools = "0.9"
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[lib]
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path = "src/lib.rs"
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@ -16,6 +16,7 @@ use aoc2020::day13;
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use aoc2020::day14;
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use aoc2020::day15;
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use aoc2020::day16;
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use aoc2020::day17;
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fn aoc2020_all(c: &mut Criterion) {
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c.bench_function("day01", |b| b.iter(|| day01::run().unwrap()));
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@ -34,6 +35,7 @@ fn aoc2020_all(c: &mut Criterion) {
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c.bench_function("day14", |b| b.iter(|| day14::run().unwrap()));
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c.bench_function("day15", |b| b.iter(|| day15::run().unwrap()));
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c.bench_function("day16", |b| b.iter(|| day16::run().unwrap()));
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c.bench_function("day17", |b| b.iter(|| day17::run().unwrap()));
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}
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criterion_group! {
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8
aoc2020/input/day17.txt
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8
aoc2020/input/day17.txt
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@ -0,0 +1,8 @@
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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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3
aoc2020/input/day17_provided.txt
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3
aoc2020/input/day17_provided.txt
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@ -0,0 +1,3 @@
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.#.
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..#
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###
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110
aoc2020/src/day17.rs
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110
aoc2020/src/day17.rs
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@ -0,0 +1,110 @@
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use std::collections::HashSet;
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use std::fmt::Write;
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use anyhow::{anyhow, Result};
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use itertools::iproduct;
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const INPUT: &str = include_str!("../input/day17.txt");
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pub fn run() -> Result<String> {
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let mut res = String::with_capacity(128);
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writeln!(res, "part 1: {}", part1(INPUT)?)?;
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Ok(res)
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}
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fn part1(input: &str) -> Result<usize> {
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let mut pocket_dim: PocketDimension = input.parse()?;
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for _ in 0..6 {
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pocket_dim.update();
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}
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Ok(pocket_dim.points.len())
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}
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type Point = (i64, i64, i64);
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struct PocketDimension {
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points: HashSet<Point>,
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}
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impl PocketDimension {
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fn neighbours(point: Point) -> impl Iterator<Item = Point> {
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iproduct!(-1..=1, -1..=1, -1..=1)
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.filter(|(x, y, z)| *x != 0 || *y != 0 || *z != 0)
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.map(move |(dx, dy, dz)| (point.0 + dx, point.1 + dy, point.2 + dz))
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}
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fn active_neighbours(&self, point: Point) -> usize {
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Self::neighbours(point)
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.filter(|p| self.points.contains(p))
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.count()
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}
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fn update(&mut self) {
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let mut processed: HashSet<Point> = HashSet::new();
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let mut new = self.points.clone();
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for point in &self.points {
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for neighbour in Self::neighbours(*point).chain(std::iter::once(*point)) {
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if processed.contains(&neighbour) {
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continue;
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}
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processed.insert(neighbour);
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// if point is active
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if self.points.contains(&neighbour) {
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if !(2..=3).contains(&self.active_neighbours(neighbour)) {
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// now inactive
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new.remove(&neighbour);
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}
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} else if self.active_neighbours(neighbour) == 3 {
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new.insert(neighbour);
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}
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}
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}
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self.points = new;
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}
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}
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impl std::str::FromStr for PocketDimension {
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type Err = anyhow::Error;
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fn from_str(s: &str) -> Result<Self> {
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let points = s
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.lines()
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.enumerate()
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.flat_map(|(i, line)| {
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line.chars().enumerate().filter_map(move |(j, c)| match c {
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'#' => Some(Ok((i as i64, j as i64, 0))),
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'.' => None,
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_ => Some(Err(anyhow!("unexpected char: `{}`", c))),
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})
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})
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.collect::<Result<_>>()?;
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Ok(Self { points })
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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const PROVIDED: &str = include_str!("../input/day17_provided.txt");
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#[test]
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fn part1_provided() {
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assert_eq!(part1(PROVIDED).unwrap(), 112);
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}
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#[test]
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fn part1_real() {
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assert_eq!(part1(INPUT).unwrap(), 336);
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}
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}
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@ -16,3 +16,4 @@ pub mod day13;
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pub mod day14;
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pub mod day15;
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pub mod day16;
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pub mod day17;
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@ -18,6 +18,7 @@ use aoc2020::day13;
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use aoc2020::day14;
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use aoc2020::day15;
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use aoc2020::day16;
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use aoc2020::day17;
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fn main() -> Result<()> {
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let days: &[DayFunc] = &[
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@ -37,6 +38,7 @@ fn main() -> Result<()> {
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day14::run,
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day15::run,
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day16::run,
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day17::run,
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];
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aoc::run(days)
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