104 lines
2.2 KiB
Rust
104 lines
2.2 KiB
Rust
#![feature(test)]
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extern crate test;
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use std::time::Duration;
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use aoc2021::{
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common::*,
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grid::{Grid, PositionND},
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};
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const DAY: usize = 11;
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const ROUNDS: usize = 100;
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type Parsed = Grid<u8, 2>;
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fn parse_input(raw: &str) -> Parsed {
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Grid::<u8, 2>::from_bytes_2d(raw, |b: u8| b - b'0')
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}
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fn part1(parsed: &Parsed) -> usize {
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let mut grid = parsed.to_owned();
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let mut flashed = Vec::new();
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let mut flashes = 0;
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for _ in 0..ROUNDS {
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for (p, energy) in grid.fields.iter_mut() {
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*energy += 1;
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if energy == &10 {
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flashed.push(*p);
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}
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}
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for p in flashed.clone() {
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flash(&mut grid, p, &mut flashed);
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}
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flashes += flashed.len();
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for p in flashed.drain(..) {
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*grid.fields.get_mut(&p).unwrap() = 0;
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}
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}
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flashes
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}
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fn flash(grid: &mut Parsed, position: PositionND<2>, flashed: &mut Vec<PositionND<2>>) {
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for n in position.neighbors() {
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if let Some(p) = grid.fields.get_mut(&n) {
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*p += 1;
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if p == &10 {
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flashed.push(n);
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flash(grid, n, flashed);
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}
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}
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}
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}
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fn part2(parsed: &Parsed) -> usize {
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let mut grid = parsed.to_owned();
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let mut flashed = Vec::new();
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for i in 1.. {
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for (p, energy) in grid.fields.iter_mut() {
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*energy += 1;
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if energy == &10 {
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flashed.push(*p);
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}
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}
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for p in flashed.clone() {
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flash(&mut grid, p, &mut flashed);
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}
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if flashed.len() == parsed.len() {
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return i;
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}
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for p in flashed.drain(..) {
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*grid.fields.get_mut(&p).unwrap() = 0;
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}
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}
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unreachable!()
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}
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fn main() {
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let input = parse_input(&read_file(DAY));
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println!("Part 1: {}", part1(&input));
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println!("Part 2: {}", part2(&input));
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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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use aoc2021::*;
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const TEST_INPUT: &str = "5483143223
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2745854711
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5264556173
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6141336146
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6357385478
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4167524645
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2176841721
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6882881134
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4846848554
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5283751526";
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test!(part1() == 1656);
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test!(part2() == 195);
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bench!(part1() == 1741);
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bench!(part2() == 440);
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bench_input!(Grid::len => 100);
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}
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