89 lines
2.5 KiB
Rust
89 lines
2.5 KiB
Rust
#![feature(int_abs_diff)]
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#![feature(test)]
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extern crate test;
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use aoc2021::common::*;
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const DAY: usize = 5;
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type Coordinate = (i16, i16); // twice as fast as using i64s ¯\_(ツ)_/¯
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type Parsed = Vec<(Coordinate, Coordinate)>;
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// Memes :pepeHype:
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/*
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macro_rules! parse {
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($($x1: literal, $y1: literal -> $x2: literal, $y2: literal)*) => {
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[ $((($x1, $y1), ($x2, $y2)),)* ]
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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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raw.lines()
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.filter_map(|line| line.split_once(" -> "))
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.filter_map(|(c1, c2)| c1.split_once(',').zip(c2.split_once(',')))
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.map(|((x1, y1), (x2, y2))| ((x1.parse().unwrap(), y1.parse().unwrap()), (x2.parse().unwrap(), y2.parse().unwrap())))
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.collect()
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}
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fn solve<F: FnMut(&(Coordinate, Coordinate)) -> Vec<Coordinate>>(parsed: &Parsed, f: F) -> usize {
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let max_x = *parsed.iter().flat_map(|((x1, _), (x2, _))| [x1, x2]).max().unwrap() + 2;
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let max_y = *parsed.iter().flat_map(|((_, y1), (_, y2))| [y1, y2]).max().unwrap() + 2;
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let mut counts = vec![vec![0; max_x as _]; max_y as _];
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parsed.iter().flat_map(f).for_each(|(x, y)| counts[x as usize][y as usize] += 1);
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counts.into_iter().flatten().filter(|n| n > &1).count()
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}
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fn part1(parsed: &Parsed) -> usize {
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solve(parsed, |&cs| match cs {
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((x1, y1), (x2, y2)) if x1 == x2 => (y1.min(y2)..=y1.max(y2)).map(|y| (x1, y)).collect(),
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((x1, y1), (x2, y2)) if y1 == y2 => (x1.min(x2)..=x1.max(x2)).map(|x| (x, y1)).collect(),
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_ => vec![],
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})
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}
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fn part2(parsed: &Parsed) -> usize {
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let offset = |x1, x2| (x1 < x2) as i16 - (x1 > x2) as i16;
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solve(parsed, |&((mut x1, mut y1), (x2, y2))| {
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let mut coords = Vec::with_capacity(x1.abs_diff(x2).max(y1.abs_diff(y2)) as usize + 1);
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let x_offset = offset(x1, x2);
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let y_offset = offset(y1, y2);
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loop {
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coords.push((x1, y1));
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if x1 == x2 && y1 == y2 {
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break;
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}
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x1 += x_offset;
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y1 += y_offset;
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}
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coords
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})
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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 = "0,9 -> 5,9
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8,0 -> 0,8
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9,4 -> 3,4
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2,2 -> 2,1
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7,0 -> 7,4
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6,4 -> 2,0
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0,9 -> 2,9
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3,4 -> 1,4
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0,0 -> 8,8
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5,5 -> 8,2";
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test!(part1() == 5);
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test!(part2() == 12);
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bench!(part1() == 5280);
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bench!(part2() == 16716);
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bench_input!(Vec::len => 500);
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}
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