advent-of-code/2020/src/bin/day17.rs

112 lines
3.2 KiB
Rust

#![allow(incomplete_features)]
#![feature(test, const_generics, const_evaluatable_checked)]
extern crate test;
use aoc2020::{
common::*, grid::{cell::Cell, *}
};
use itertools::Itertools;
fn read_input() -> String {
read_file(17)
}
fn parse_input<const DIMS: usize, F: FnMut((usize, usize)) -> PositionND<DIMS> + Copy>(raw: &str, mut pos_gen: F) -> Grid<DIMS, Cell> {
raw.lines()
.enumerate()
.flat_map(move |(y, l)| {
l.bytes()
.enumerate()
.map(move |(x, b)| (PositionND::<DIMS>::from_padded(&[x as i64, y as i64]), b.into()))
})
.filter(|(_, c)| c == &Cell::Alive)
.collect()
}
fn count_live_neighbors<const D: usize>(p: PositionND<D>, grid: &Grid<D, Cell>) -> usize {
p.neighbors().iter().filter(|&n| grid.get(n) == Cell::Alive).count()
}
fn make_step<const D: usize>(input: Grid<D, Cell>) -> Grid<D, Cell> {
let readonly = input.clone();
input
.fields
.keys()
.flat_map(|p| p.neighbors().iter())
.unique()
.map(|pos| {
let cell = readonly.get(&pos);
let new = match (&cell, count_live_neighbors::<D>(&pos, &readonly)) {
(Cell::Alive, 2..=3) => Cell::Alive,
(Cell::Dead, 3) => Cell::Alive,
_ => Cell::Dead,
};
(pos, new)
})
.filter(|(_, c)| c == &Cell::Alive)
.collect()
}
fn solve<const D: usize>(parsed: &Grid<D, Cell>, steps: usize) -> usize {
let mut clone = parsed.clone();
for _ in 0..steps {
clone = make_step(clone);
}
clone.fields.into_iter().filter(|(_, c)| c == &Cell::Alive).count()
}
fn main() {
let raw = read_input();
let input = parse_input(&raw, |(x, y)| Position3D::from((x, y, 0)));
println!("Part 1: {}", solve(&input, 6));
let input = parse_input(&raw, |(x, y)| Position4D::from((x, y, 0, 0)));
println!("Part 2: {}", solve(&input, 6));
}
#[cfg(test)]
mod tests {
use super::*;
use aoc2020::*;
use test::black_box;
const TEST_INPUT: &str = ".#.
..#
###";
#[test]
fn test_3d() {
let input = parse_input(TEST_INPUT, |(x, y)| Position3D::from((x, y, 0)));
assert_eq!(solve(&input, 6), 112);
}
#[test]
fn test_4d() {
let input = parse_input(TEST_INPUT, |(x, y)| Position4D::from((x, y, 0, 0)));
assert_eq!(solve(&input, 6), 848);
}
#[bench]
fn bench_3d_parse(b: &mut test::Bencher) {
let raw = read_input();
b.iter(|| assert_eq!(parse_input(black_box(&raw), |(x, y)| Position3D::from((x, y, 0))).fields.len(), 43));
}
#[bench]
#[rustfmt::skip]
fn bench_4d_parse(b: &mut test::Bencher) {
let raw = read_input();
b.iter(|| assert_eq!(parse_input(black_box(&raw), |(x, y)| Position4D::from((x, y, 0, 0))).fields.len(), 43));
}
#[bench]
fn bench_3d(b: &mut test::Bencher) {
let input = parse_input(&read_input(), |(x, y)| Position3D::from((x, y, 0)));
b.iter(|| assert_eq!(solve(&input, 6), 348));
}
#[bench]
fn bench_4d(b: &mut test::Bencher) {
let input = parse_input(&read_input(), |(x, y)| Position4D::from((x, y, 0, 0)));
b.iter(|| assert_eq!(solve(&input, 6), 2236));
}
}