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day20.rs
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day20.rs
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use std::{collections::HashMap, fmt::Display, time::Instant};
use std::{collections::HashSet, fs};
enum ImageProcessingMode {
Flip,
Rotate,
}
#[derive(Clone, Debug, Eq, Hash, PartialEq)]
struct Tile {
id: usize,
pixels: Vec<Vec<char>>,
top_border: Vec<char>,
bottom_border: Vec<char>,
left_border: Vec<char>,
right_border: Vec<char>,
}
impl Display for Tile {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
writeln!(f, "id: {}", self.id)?;
for i in 0..self.pixels.len() {
for j in 0..self.pixels[0].len() {
write!(f, "{}", self.pixels[i][j])?;
}
writeln!(f)?;
}
Ok(())
}
}
impl Tile {
fn default() -> Self {
Self {
id: 0,
pixels: vec![vec![' '; 10]; 10],
top_border: vec![' '; 10],
bottom_border: vec![' '; 10],
left_border: vec![' '; 10],
right_border: vec![' '; 10],
}
}
fn from_raw_data(data: &str) -> Self {
let lines: Vec<&str> = data.lines().collect();
let id: usize = lines[0]
.replace(':', " ")
.split_whitespace()
.nth(1)
.unwrap()
.parse()
.unwrap();
let pixels: Vec<Vec<char>> = lines
.iter()
.skip(1)
.map(|line| line.chars().collect())
.collect();
let top_border = pixels[0].clone();
let bottom_border = pixels[pixels.len() - 1].clone();
let left_border = pixels.iter().map(|l| l[0]).collect();
let right_border = pixels.iter().map(|l| l[l.len() - 1]).collect();
Self {
id,
pixels,
top_border,
bottom_border,
left_border,
right_border,
}
}
fn flip(&mut self) {
let origin = self.clone();
self.pixels = process_image(ImageProcessingMode::Flip, &origin.pixels);
std::mem::swap(&mut self.right_border, &mut self.left_border);
self.top_border = Self::reverse_border(&origin.top_border);
self.bottom_border = Self::reverse_border(&origin.bottom_border);
}
fn rotate(&mut self) {
let origin = self.clone();
self.pixels = process_image(ImageProcessingMode::Rotate, &origin.pixels);
self.right_border = origin.top_border;
self.top_border = Self::reverse_border(&origin.left_border);
self.left_border = origin.bottom_border;
self.bottom_border = Self::reverse_border(&origin.right_border);
}
fn reverse_border(border: &[char]) -> Vec<char> {
border.iter().rev().copied().collect()
}
fn orientation_options(tile: &Tile) -> Vec<Tile> {
let tile_r0 = tile.clone();
let mut tile_r1 = tile_r0.clone();
tile_r1.rotate();
let mut tile_r2 = tile_r1.clone();
tile_r2.rotate();
let mut tile_r3 = tile_r2.clone();
tile_r3.rotate();
let mut tile_f0 = tile_r0.clone();
tile_f0.flip();
let mut tile_f1 = tile_r1.clone();
tile_f1.flip();
let mut tile_f2 = tile_r2.clone();
tile_f2.flip();
let mut tile_f3 = tile_r3.clone();
tile_f3.flip();
vec![
tile_r0, tile_r1, tile_r2, tile_r3, tile_f0, tile_f1, tile_f2, tile_f3,
]
}
fn remove_borders(tile: &Tile) -> Vec<Vec<char>> {
let mut borderless = vec![vec![' '; tile.pixels[0].len() - 2]; tile.pixels.len() - 2];
for y in 1..tile.pixels.len() - 1 {
for x in 1..tile.pixels[0].len() - 1 {
borderless[x - 1][y - 1] = tile.pixels[x][y];
}
}
borderless
}
}
fn process_image(mode: ImageProcessingMode, origin: &[Vec<char>]) -> Vec<Vec<char>> {
let mut processed = match mode {
ImageProcessingMode::Flip => origin.to_vec(),
ImageProcessingMode::Rotate => {
vec![vec![' '; origin.len()]; origin[0].len()]
}
};
for y in 0..processed.len() {
for x in 0..processed[0].len() {
match mode {
ImageProcessingMode::Flip => {
processed[y][x] = origin[y][processed[y].len() - x - 1]
}
ImageProcessingMode::Rotate => {
processed[y][x] = origin[processed[y].len() - x - 1][y]
}
}
}
}
processed
}
fn solve_puzzle(tiles: &[Tile]) -> HashMap<(i32, i32), Tile> {
let mut final_puzzle: HashMap<(i32, i32), Tile> = HashMap::new();
let mut unplaced_tiles = HashSet::new();
unplaced_tiles.insert(((0, 0), tiles[0].clone()));
let mut unused_tiles: HashSet<Tile> = tiles.iter().skip(1).cloned().collect();
while let Some(((cur_x, cur_y), cur_tile)) = unplaced_tiles.iter().next().cloned() {
for unused_tile in unused_tiles.clone().iter() {
for orientation in Tile::orientation_options(unused_tile) {
if orientation.left_border == cur_tile.right_border {
unplaced_tiles.insert(((cur_x + 1, cur_y), orientation));
unused_tiles.remove(unused_tile);
break;
} else if orientation.right_border == cur_tile.left_border {
unplaced_tiles.insert(((cur_x - 1, cur_y), orientation));
unused_tiles.remove(unused_tile);
break;
} else if orientation.bottom_border == cur_tile.top_border {
unplaced_tiles.insert(((cur_x, cur_y - 1), orientation));
unused_tiles.remove(unused_tile);
break;
} else if orientation.top_border == cur_tile.bottom_border {
unplaced_tiles.insert(((cur_x, cur_y + 1), orientation));
unused_tiles.remove(unused_tile);
break;
}
}
}
unplaced_tiles.remove(&((cur_x, cur_y), cur_tile.clone()));
final_puzzle.insert((cur_x, cur_y), cur_tile);
}
final_puzzle
}
fn relocate(puzzle_map: &HashMap<(i32, i32), Tile>) -> Vec<Vec<Tile>> {
let min_x = puzzle_map.iter().min_by_key(|(pos, _)| pos.0).unwrap().0 .0;
let max_x = puzzle_map.iter().max_by_key(|(pos, _)| pos.0).unwrap().0 .0;
let min_y = puzzle_map.iter().min_by_key(|(pos, _)| pos.1).unwrap().0 .1;
let max_y = puzzle_map.iter().max_by_key(|(pos, _)| pos.1).unwrap().0 .1;
let mut relocated_puzzle =
vec![vec![Tile::default(); (max_x - min_x + 1) as usize]; (max_y - min_y + 1) as usize];
for ((xi, yi), cur_tile) in puzzle_map.iter() {
relocated_puzzle[(yi - min_y) as usize][(xi - min_x) as usize] = cur_tile.clone();
}
relocated_puzzle
}
#[derive(Clone)]
struct SeaMonster {
pixels: Vec<Vec<char>>,
}
impl SeaMonster {
fn new() -> Self {
Self {
pixels: vec![
" # ".chars().collect(),
"# ## ## ###".chars().collect(),
" # # # # # # ".chars().collect(),
],
}
}
fn flip(&mut self) {
self.pixels = process_image(ImageProcessingMode::Flip, &self.pixels.clone());
}
fn rotate(&mut self) {
self.pixels = process_image(ImageProcessingMode::Rotate, &self.pixels.clone());
}
fn height(&self) -> usize {
self.pixels.len()
}
fn width(&self) -> usize {
self.pixels[0].len()
}
fn coords(&self) -> Vec<(usize, usize)> {
let mut coords = vec![];
for y in 0..self.pixels.len() {
for x in 0..self.pixels[0].len() {
if self.pixels[y][x] == '#' {
coords.push((x, y));
}
}
}
coords
}
fn orientation_options() -> Vec<SeaMonster> {
let sea_monster_r0 = SeaMonster::new();
let mut sea_monster_r1 = sea_monster_r0.clone();
sea_monster_r1.rotate();
let mut sea_monster_r2 = sea_monster_r1.clone();
sea_monster_r2.rotate();
let mut sea_monster_r3 = sea_monster_r2.clone();
sea_monster_r3.rotate();
let mut sea_monster_f0 = sea_monster_r0.clone();
sea_monster_f0.flip();
let mut sea_monster_f1 = sea_monster_r1.clone();
sea_monster_f1.flip();
let mut sea_monster_f2 = sea_monster_r2.clone();
sea_monster_f2.flip();
let mut sea_monster_f3 = sea_monster_r3.clone();
sea_monster_f3.flip();
vec![
sea_monster_r0,
sea_monster_r1,
sea_monster_r2,
sea_monster_r3,
sea_monster_f0,
sea_monster_f1,
sea_monster_f2,
sea_monster_f3,
]
}
}
type Picture = Vec<Vec<char>>;
fn create_picture(solved_puzzle: &HashMap<(i32, i32), Tile>) -> Picture {
let relocated_puzzle = relocate(solved_puzzle);
let mut sub_pictures: Vec<Vec<Picture>> = vec![];
for row in relocated_puzzle.iter() {
let mut tmp: Vec<Picture> = vec![];
for tile in row.iter() {
tmp.push(Tile::remove_borders(tile));
}
sub_pictures.push(tmp);
}
let tile_width = sub_pictures[0][0][0].len();
let tile_height = sub_pictures[0][0].len();
let puzzle_width = sub_pictures[0].len();
let puzzle_height = sub_pictures.len();
let mut picture = vec![vec![' '; tile_width * puzzle_width]; tile_height * puzzle_height];
for (i, r) in sub_pictures.iter().enumerate() {
for (j, tile) in r.iter().enumerate() {
for (off_i, tr) in tile.iter().enumerate() {
for (off_j, p) in tr.iter().enumerate() {
picture[i * tile_height + off_i][j * tile_width + off_j] = *p;
}
}
}
}
picture
}
fn count_sea_monsters(picture: &[Vec<char>]) -> usize {
let mut count = 0;
for monster_orientation in SeaMonster::orientation_options() {
for i in 0..picture.len() - monster_orientation.height() {
for j in 0..picture[0].len() - monster_orientation.width() {
if monster_orientation
.coords()
.iter()
.all(|(xm, ym)| picture[i + ym][j + xm] == '#')
{
count += 1;
}
}
}
}
count
}
struct Solution;
impl Solution {
fn part1(tiles: &[Tile]) -> usize {
let solved_puzzle: HashMap<(i32, i32), Tile> = solve_puzzle(tiles);
let relocated_puzzle = relocate(&solved_puzzle);
let puzzle_width = relocated_puzzle[0].len();
let puzzle_height = relocated_puzzle.len();
relocated_puzzle[0][0].id
* relocated_puzzle[0][puzzle_width - 1].id
* relocated_puzzle[puzzle_height - 1][puzzle_width - 1].id
* relocated_puzzle[puzzle_height - 1][0].id
}
fn part2(tiles: &[Tile]) -> usize {
let solved_puzzle = solve_puzzle(tiles);
let picture = create_picture(&solved_puzzle);
let num_sea_monsters = count_sea_monsters(&picture);
let num_pixel_sea_monster = 15;
picture.iter().flatten().filter(|&p| *p == '#').count()
- num_sea_monsters * num_pixel_sea_monster
}
}
fn main() {
let input = fs::read_to_string("./input/day20.txt").expect("File not found!");
let tiles: Vec<Tile> = input
.trim()
.split("\n\n")
.map(Tile::from_raw_data)
.collect();
let timer = Instant::now();
println!(
"p1: {} (runtime: {:?})",
Solution::part1(&tiles),
timer.elapsed()
);
let timer = Instant::now();
println!(
"p2: {} (runtime: {:?})",
Solution::part2(&tiles),
timer.elapsed()
);
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_day20() {
let input = "\
Tile 2311:
..##.#..#.
##..#.....
#...##..#.
####.#...#
##.##.###.
##...#.###
.#.#.#..##
..#....#..
###...#.#.
..###..###
Tile 1951:
#.##...##.
#.####...#
.....#..##
#...######
.##.#....#
.###.#####
###.##.##.
.###....#.
..#.#..#.#
#...##.#..
Tile 1171:
####...##.
#..##.#..#
##.#..#.#.
.###.####.
..###.####
.##....##.
.#...####.
#.##.####.
####..#...
.....##...
Tile 1427:
###.##.#..
.#..#.##..
.#.##.#..#
#.#.#.##.#
....#...##
...##..##.
...#.#####
.#.####.#.
..#..###.#
..##.#..#.
Tile 1489:
##.#.#....
..##...#..
.##..##...
..#...#...
#####...#.
#..#.#.#.#
...#.#.#..
##.#...##.
..##.##.##
###.##.#..
Tile 2473:
#....####.
#..#.##...
#.##..#...
######.#.#
.#...#.#.#
.#########
.###.#..#.
########.#
##...##.#.
..###.#.#.
Tile 2971:
..#.#....#
#...###...
#.#.###...
##.##..#..
.#####..##
.#..####.#
#..#.#..#.
..####.###
..#.#.###.
...#.#.#.#
Tile 2729:
...#.#.#.#
####.#....
..#.#.....
....#..#.#
.##..##.#.
.#.####...
####.#.#..
##.####...
##..#.##..
#.##...##.
Tile 3079:
#.#.#####.
.#..######
..#.......
######....
####.#..#.
.#...#.##.
#.#####.##
..#.###...
..#.......
..#.###...";
let tiles: Vec<Tile> = input
.trim()
.split("\n\n")
.map(Tile::from_raw_data)
.collect();
assert_eq!(Solution::part1(&tiles), 20899048083289);
assert_eq!(Solution::part2(&tiles), 273);
}
}