124 lines
2.9 KiB
Rust
124 lines
2.9 KiB
Rust
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#![feature(test)]
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extern crate test;
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use aoc2021::common::*;
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use itertools::Itertools;
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const DAY: usize = 13;
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type Parsed = (Vec<Vec<bool>>, Vec<Fold>);
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enum Fold {
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X(usize),
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Y(usize),
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}
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impl Fold {
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fn fold(&self, grid: &mut Vec<Vec<bool>>) {
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match *self {
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Fold::X(at) => {
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for x in 0..at {
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for y in 0..grid[x].len() {
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grid[x][y] |= grid[at + at - x][y];
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}
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}
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grid.truncate(at);
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}
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Fold::Y(at) => {
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for ys in grid {
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for y in 0..at {
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ys[y] |= *ys.get(at + at - y).unwrap_or(&false);
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}
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ys.truncate(at);
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}
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}
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}
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}
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}
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fn parse_input(raw: &str) -> Parsed {
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let (points, folds) = raw.split_once("\n\n").unwrap();
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let points: Vec<(usize, usize)> =
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points.lines().map(|line| line.split_once(',').unwrap()).map(|(x, y)| (parse_num(x), parse_num(y))).collect();
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let mut grid = vec![vec![false; points.iter().map(|&(_, y)| y).max().unwrap() + 1]; points.iter().map(|&(x, _)| x).max().unwrap() + 1];
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println!("allocated x {} and y {}", grid.len(), grid[0].len());
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for (x, y) in points {
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grid[x][y] = true;
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}
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let folds = folds
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.lines()
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.map(|line| {
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if let Some(x) = line.strip_prefix("fold along x=") {
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Fold::X(parse_num(x))
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} else if let Some(y) = line.strip_prefix("fold along y=") {
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Fold::Y(parse_num(y))
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} else {
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unreachable!("{}", line)
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}
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})
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.collect();
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(grid, folds)
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}
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fn part1((grid, folds): &Parsed) -> usize {
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let mut folded = grid.to_owned();
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folds[0].fold(&mut folded);
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folded.into_iter().flatten().filter(|&b| b).count()
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}
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fn part2((grid, instructions): &Parsed) -> String {
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let mut paper = grid.to_owned();
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for instruction in instructions {
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instruction.fold(&mut paper); // :thanking:
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}
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paper.into_iter().map(|ys| ys.into_iter().map(|b| if b { '#' } else { ' ' }).collect::<String>()).join("\n")
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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 = "6,10
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0,14
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9,10
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0,3
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10,4
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4,11
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6,0
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6,12
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4,1
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0,13
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10,12
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3,4
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3,0
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8,4
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1,10
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2,14
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8,10
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9,0
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fold along y=7
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fold along x=5";
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test!(part1() == 17);
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// test!(part2() == 0);
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bench!(part1() == 661);
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// bench!(part2() == 0);
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bench_input!(input_len_for_bench => 1323);
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#[bench]
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fn bench_part2(b: &mut test::Bencher) {
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let parsed = parse_input(&read_file(DAY));
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b.iter(|| assert_eq!(part2(&parsed).len(), 279));
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}
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fn input_len_for_bench((grid, folds): &Parsed) -> usize {
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grid.len() + folds.len()
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}
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}
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