92 lines
2.2 KiB
Rust
92 lines
2.2 KiB
Rust
use std::collections::HashSet;
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use std::str::FromStr;
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enum Axis {
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X,
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Y,
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}
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struct FoldInstruction {
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axis: Axis,
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position: usize,
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}
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impl FoldInstruction {
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fn wrap(&self, dot: (usize, usize)) -> (usize, usize) {
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match self.axis {
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Axis::X if dot.0 >= self.position => (2 * self.position - dot.0, dot.1),
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Axis::Y if dot.1 >= self.position => (dot.0, 2 * self.position - dot.1),
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_ => (dot.0, dot.1),
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}
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}
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}
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impl FromStr for FoldInstruction {
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type Err = ();
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fn from_str(s: &str) -> Result<FoldInstruction, Self::Err> {
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let (a, p) = s[11..].split_once('=').unwrap();
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let axis = match a {
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"x" => Axis::X,
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"y" => Axis::Y,
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_ => return Err(()),
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};
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let position = p.parse().unwrap();
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Ok(FoldInstruction { axis, position })
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}
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}
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fn main() {
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const INPUT: &str = include_str!("../inputs/day13.txt");
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let sections = INPUT.split_once("\n\n").unwrap();
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let mut dots = sections
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.0
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.lines()
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.map(|line| {
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let (a, b) = line.split_once(',').unwrap();
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(a.parse().unwrap(), b.parse().unwrap())
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})
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.collect::<Vec<(usize, usize)>>();
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let instructions = sections
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.1
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.lines()
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.map(|line| line.parse().unwrap())
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.collect::<Vec<FoldInstruction>>();
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let mut all_dots: HashSet<(usize, usize)> = HashSet::new();
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for dot in &dots {
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all_dots.insert(instructions[0].wrap(*dot));
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}
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println!("solution {}", all_dots.len());
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all_dots.drain();
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for instr in instructions {
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for dot in &dots {
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all_dots.insert(instr.wrap(*dot));
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}
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dots = all_dots.drain().collect();
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}
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for y in 0..6 {
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println!(
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"{}",
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(0..40)
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.map(|x| if dots.contains(&(x, y)) {
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'🟪'
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} else {
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'⬛'
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})
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.collect::<String>()
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);
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}
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}
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#[test]
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fn test_wrap_instruction() {
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let instruction = FoldInstruction {
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axis: Axis::Y,
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position: 7,
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};
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assert_eq!(instruction.wrap((3, 0)), (3, 0));
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assert_eq!(instruction.wrap((1, 10)), (1, 4));
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}
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