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www.mikescher.com/www/statics/aoc/2020/20_solution.rs

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2020-12-21 06:12:13 +01:00
use crate::common::AdventOfCodeDay;
use regex::Regex;
use strum::IntoEnumIterator;
use strum_macros::EnumIter;
use std::convert::TryInto;
use std::collections::HashMap;
use std::collections::HashSet;
#[derive(Debug, EnumIter, Clone, Copy, PartialEq, Eq, Hash)]
enum Compass { North, East, South, West }
impl Compass {
pub fn transform_back(&self, tf: Transform) -> (Self, bool) {
return match tf {
Transform::None => match self {
Compass::North => (Compass::North, false),
Compass::East => (Compass::East, false),
Compass::South => (Compass::South, false),
Compass::West => (Compass::West, false),
},
Transform::RotCW090 => match self {
Compass::North => (Compass::West, false),
Compass::East => (Compass::North, false),
Compass::South => (Compass::East, false),
Compass::West => (Compass::South, false),
},
Transform::RotCW180 => match self {
Compass::North => (Compass::South, false),
Compass::East => (Compass::West, false),
Compass::South => (Compass::North, false),
Compass::West => (Compass::East, false),
},
Transform::RotCW270 => match self {
Compass::North => (Compass::East, false),
Compass::East => (Compass::South, false),
Compass::South => (Compass::West, false),
Compass::West => (Compass::North, false),
},
Transform::Flipped => match self {
Compass::North => (Compass::West, true),
Compass::East => (Compass::South, true),
Compass::South => (Compass::East, true),
Compass::West => (Compass::North, true),
},
Transform::RotCW090Flipped => match self {
Compass::North => (Compass::North, true),
Compass::East => (Compass::West, true),
Compass::South => (Compass::South, true),
Compass::West => (Compass::East, true),
},
Transform::RotCW180Flipped => match self {
Compass::North => (Compass::East, true),
Compass::East => (Compass::North, true),
Compass::South => (Compass::West, true),
Compass::West => (Compass::South, true),
},
Transform::RotCW270Flipped => match self {
Compass::North => (Compass::South, true),
Compass::East => (Compass::East, true),
Compass::South => (Compass::North, true),
Compass::West => (Compass::West, true),
},
};
}
}
#[derive(Debug, EnumIter, Clone, Copy, PartialEq, Eq, Hash)]
enum Transform {
None,
RotCW090,
RotCW180,
RotCW270,
Flipped,
RotCW090Flipped,
RotCW180Flipped,
RotCW270Flipped,
}
struct Tile {
id: u32,
bitmap: [[bool;10];10],
sides: HashMap<(Compass, bool), (u32,u32)>,
}
pub struct Day20 {
input: [[Tile;12];12],
}
fn new_tile_array() -> [[Tile;12];12] {
let mut vec = Vec::<[Tile;12]>::with_capacity(12);
for _ in 0..12 {
let mut inner = Vec::<Tile>::with_capacity(12);
for _ in 0..12 {
inner.push(Tile{ id: 0, bitmap: [[false;10];10], sides: HashMap::with_capacity(4*2) });
}
vec.push(inner.try_into().unwrap_or_else(|_|panic!()));
}
return vec.try_into().unwrap_or_else(|_|panic!())
}
impl Day20 {
pub fn new() -> Self {
let input_bytes = include_bytes!("../res/20_input.txt");
let input_str = String::from_utf8_lossy(input_bytes);
let rex = Regex::new(r"Tile (?P<id>[0-9]+):\n(?P<bmp>([.#]{10}\n){10})").unwrap();
let mut tiles = new_tile_array();
let mut i = 0;
for cap in rex.captures_iter(&input_str)
{
tiles[i/12][i%12].id = cap.name("id").unwrap().as_str().parse::<u32>().unwrap();
let raw = cap.name("bmp").unwrap().as_str().lines().map(|l| l.chars().collect::<Vec<char>>()).collect::<Vec<Vec<char>>>();
for y in 0..10 {
for x in 0..10 {
tiles[i/12][i%12].bitmap[y][x] = raw[y][x]=='#';
}
}
tiles[i/12][i%12].gen_cache();
i+=1;
}
Self {
input: tiles
}
}
}
impl Day20 {
fn format_ids(tiles: &[[Tile;12];12]) -> String {
let mut r = String::new();
for y in 0..12 {
for x in 0..12 {
let pad = format!(" {}", tiles[y][x].id);
r.push_str(&pad);
}
r.push('\n');
}
return r;
}
fn format_bitmaps(tiles: &[[Tile;12];12]) -> String {
let mut r = String::with_capacity(12*12*12*12 + 1000);
for y in 0..(12 * 11) {
for x in 0..(12 * 11) {
let gx = x / 11;
let gy = y / 11;
let ix = x % 11;
let iy = y % 11;
if ix==10 || iy == 10 { r.push(' '); continue; }
r.push(match tiles[gy][gx].bitmap[iy][ix] {
true => '#',
false => '.',
});
}
r.push('\n');
}
return r;
}
fn corner_to_transform_tl(tfs: Vec<(Compass, bool)>) -> Vec<Transform> {
let rtf = tfs.iter().map(|(c,_)| *c).collect::<Vec<Compass>>();
if rtf.contains(&Compass::West) && rtf.contains(&Compass::North) { return vec![Transform::RotCW180, Transform::RotCW180Flipped]; }
if rtf.contains(&Compass::North) && rtf.contains(&Compass::East) { return vec![Transform::RotCW270, Transform::RotCW270Flipped]; }
if rtf.contains(&Compass::East) && rtf.contains(&Compass::South) { return vec![Transform::None, Transform::Flipped]; }
if rtf.contains(&Compass::South) && rtf.contains(&Compass::West) { return vec![Transform::RotCW090, Transform::RotCW090Flipped]; }
panic!();
}
fn is_valid_neigbour_horz(left: &(&Tile, Transform), right: &(&Tile, Transform)) -> bool {
let s1 = left.0.get_side_after_transform(Compass::East, left.1);
let s2 = right.0.get_side_after_transform(Compass::West, right.1);
return s1.0 == s2.1;
}
fn is_valid_neigbour_vert(top: &(&Tile, Transform), bottom: &(&Tile, Transform)) -> bool {
let s1 = top.0.get_side_after_transform(Compass::South, top.1);
let s2 = bottom.0.get_side_after_transform(Compass::North, bottom.1);
return s1.0 == s2.1;
}
fn is_valid_candidate(x: usize, y: usize, tile: &Tile, transform: Transform, map: &HashMap::<(usize, usize), Vec<(&Tile, Transform)>>) -> bool {
if x > 0 {
if !map.get(&(x-1, y)).unwrap().iter().any(|t| Self::is_valid_neigbour_horz(t, &(tile, transform))) {
return false;
}
}
if x < 11 {
if !map.get(&(x+1, y)).unwrap().iter().any(|t| Self::is_valid_neigbour_horz(&(tile, transform), t)) {
return false;
}
}
if y > 0 {
if !map.get(&(x, y-1)).unwrap().iter().any(|t| Self::is_valid_neigbour_vert(t, &(tile, transform))) {
return false;
}
}
if y < 11 {
if !map.get(&(x, y+1)).unwrap().iter().any(|t| Self::is_valid_neigbour_vert(&(tile, transform), t)) {
return false;
}
}
return true;
}
fn reconstruct(tiles: &Vec<&Tile>) -> [[Tile;12];12] {
let mut candidates = HashMap::<(usize, usize), Vec<(&Tile, Transform)>>::with_capacity(12*12);
for y in 0..12 {
for x in 0..12 {
candidates.insert((x,y), tiles.iter().flat_map(|tile| Transform::iter().map(move |tf| (*tile, tf))).collect());
}
}
let corners_tl = tiles.iter()
.map(|t| (t, t.matching_sides(&tiles)))
.filter(|(_,s)| s.len()==2)
.map(|(t,s)| (*t, Self::corner_to_transform_tl(s)))
.flat_map(|(t,s)| s.iter().map(|tf| (t, *tf)).collect::<Vec<(&Tile, Transform)>>() )
.collect::<Vec<(&Tile, Transform)>>();
let corner_tl = corners_tl.iter().skip(5).nth(0).unwrap();
verboseln!("Define [0,0] := ({}, {:?}):", corner_tl.0.id, corner_tl.1);
verboseln!("{}", corner_tl.0.transform(corner_tl.1).format_bitmap());
candidates.insert((0, 0), vec![*corner_tl]);
for yy in 0..12 {
for xx in 0..12 {
if xx== 0 && yy == 0 { continue; }
let other = candidates.get_mut(&(xx,yy)).unwrap();
other.retain(|p| p.0.id != corner_tl.0.id);
}
}
loop {
let mut ok = 0;
for y in 0..12 {
for x in 0..12 {
let cand = candidates.get(&(x,y)).unwrap();
if cand.len() == 1 { ok+=1; continue; }
let oldlen = cand.len();
let mut cand_clone = cand.clone();
cand_clone.retain(|(tile, tf)| Day20::is_valid_candidate(x, y, tile, *tf, &candidates));
if cand_clone.len() == 0 {
verboseln!("Reduced [{},{}] from {} to {} candidates", x, y, oldlen, cand_clone.len());
panic!("No more candidates after [is_valid_candidate]");
}
else if oldlen != cand_clone.len() {
if cand_clone.len() == 1 {
verboseln!(" > Found tile for [{},{}] from {} candidates := ({}, {:?}):", x, y, oldlen, cand_clone[0].0.id, cand_clone[0].1);
verboseln!("{}", cand_clone[0].0.transform(cand_clone[0].1).format_bitmap());
verboseln!();
} else {
verboseln!("Reduced [{},{}] from {} to {} candidates", x, y, oldlen, cand_clone.len());
}
if cand_clone.len() == 1 {
for yy in 0..12 {
for xx in 0..12 {
if x==xx && y==yy { continue; }
let other = candidates.get_mut(&(xx,yy)).unwrap();
let other_oldlen = other.len();
other.retain(|p| p.0.id != cand_clone[0].0.id);
if other_oldlen != other.len() {
verboseln!("Auto-force reduced [{},{}] from {} to {} candidates (triggered by [{},{}])", xx, yy, other_oldlen, other.len(), x, y);
}
if other.len() == 0 { panic!("No more candidates after [retain] in [{},{}]", xx, yy); }
}
}
}
candidates.insert((x, y), cand_clone);
}
else {
verboseln!("No changes on [{},{}] ({} candidates)", x, y, oldlen);
}
}
}
if ok == 12*12 { break; }
}
let mut tiles = new_tile_array();
for y in 0..12 {
for x in 0..12 {
tiles[y][x].id = candidates[&(x,y)][0].0.id;
tiles[y][x].bitmap = Tile::apply_transform_10(&candidates[&(x,y)][0].0.bitmap, candidates[&(x,y)][0].1);
tiles[y][x].gen_cache();
}
}
return tiles;
}
pub fn find_monsters(sea: &[[bool;8*12];8*12], str_blueprint: String) -> (Vec<(usize, usize)>, Vec<(usize, usize)>) {
let bp_width = str_blueprint.lines().nth(0).unwrap().len();
let bp_height = str_blueprint.lines().count();
let blueprint = str_blueprint
.lines()
.enumerate()
.flat_map(|(y,l)| l.chars().enumerate().filter(|(_,v)| *v=='#').map(move |(x,_)| (x,y)))
.collect::<Vec<_>>();
verboseln!("Monster: {:?}", blueprint);
let mut r = Vec::new();
for y in 0..(8*12-bp_height) {
for x in 0..(8*12-bp_width) {
if blueprint.iter().all(|(dx,dy)| sea[y + *dy][x + *dx]) { r.push((x, y)); }
}
}
let mk = r.iter()
.flat_map(|(sx,sy)| blueprint.iter().map(move |(dx,dy)| (*sx+*dx, *sy+*dy)))
.collect::<HashSet<_>>()
.iter()
.map(|p|*p)
.collect::<Vec<_>>();
return (r, mk);
}
}
impl Tile {
fn format_bitmap(&self) -> String {
let mut r = String::with_capacity(10*11);
for y in 0..10 {
for x in 0..10 {
r.push(match self.bitmap[y][x] {
true => '#',
false => '.',
});
}
r.push('\n');
}
return r;
}
fn transform(&self, tf: Transform) -> Self {
let mut r = Self {
id: self.id,
bitmap: Self::apply_transform_10(&self.bitmap, tf),
sides: HashMap::new(),
};
r.gen_cache();
return r;
}
fn apply_transform_10(src: &[[bool;10];10], tf: Transform) -> [[bool;10];10] {
let mut r = [[false;10];10];
for src_y in 0..10 {
for src_x in 0..10 {
let dst_x: usize;
let dst_y: usize;
match tf {
Transform::None => { dst_x = 0 + src_x; dst_y = 0 + src_y; },
Transform::RotCW090 => { dst_x = 9 - src_y; dst_y = 0 + src_x; },
Transform::RotCW180 => { dst_x = 9 - src_x; dst_y = 9 - src_y; },
Transform::RotCW270 => { dst_x = 0 + src_y; dst_y = 9 - src_x; },
Transform::Flipped => { dst_x = 0 + src_y; dst_y = 0 + src_x; },
Transform::RotCW090Flipped => { dst_x = 9 - src_x; dst_y = 0 + src_y; },
Transform::RotCW180Flipped => { dst_x = 9 - src_y; dst_y = 9 - src_x; },
Transform::RotCW270Flipped => { dst_x = 0 + src_x; dst_y = 9 - src_y; },
};
r[dst_y][dst_x] = src[src_y][src_x];
}
}
return r;
}
fn apply_transform_96(src: &[[bool;8*12];8*12], tf: Transform) -> [[bool;8*12];8*12] {
let mut r = [[false;8*12];8*12];
for src_y in 0..(8*12) {
for src_x in 0..(8*12) {
let dst_x: usize;
let dst_y: usize;
match tf {
Transform::None => { dst_x = 0 + src_x; dst_y = 0 + src_y; },
Transform::RotCW090 => { dst_x = 95 - src_y; dst_y = 0 + src_x; },
Transform::RotCW180 => { dst_x = 95 - src_x; dst_y = 95 - src_y; },
Transform::RotCW270 => { dst_x = 0 + src_y; dst_y = 95 - src_x; },
Transform::Flipped => { dst_x = 0 + src_y; dst_y = 0 + src_x; },
Transform::RotCW090Flipped => { dst_x = 95 - src_x; dst_y = 0 + src_y; },
Transform::RotCW180Flipped => { dst_x = 95 - src_y; dst_y = 95 - src_x; },
Transform::RotCW270Flipped => { dst_x = 0 + src_x; dst_y = 95 - src_y; },
};
r[dst_y][dst_x] = src[src_y][src_x];
}
}
return r;
}
fn side_to_int(s: &[bool;10]) -> (u32,u32) {
let mut u1=0;
for i in 0..10 {
u1 *= 2;
if s[i] { u1 += 1; }
}
let mut u2=0;
for i in 0..10 {
u2 *= 2;
if s[9-i] { u2 += 1; }
}
return (u1,u2);
}
fn get_side(&self, d: Compass, flipped: bool) -> (u32,u32) {
return *self.sides.get(&(d,flipped)).unwrap();
}
fn get_side_after_transform(&self, d: Compass, tf: Transform) -> (u32,u32) {
return *self.sides.get(&d.transform_back(tf)).unwrap();
}
fn calc_side(&self, d: Compass, flipped: bool) -> [bool;10] {
let mut r = [false;10];
match flipped {
false =>
{
match d {
Compass::North =>
{
for i in 0..10 { r[i] = self.bitmap[0][i]; }
return r;
},
Compass::East =>
{
for i in 0..10 { r[i] = self.bitmap[i][9]; }
return r;
},
Compass::South =>
{
for i in 0..10 { r[i] = self.bitmap[9][9-i]; }
return r;
},
Compass::West =>
{
for i in 0..10 { r[i] = self.bitmap[9-i][0]; }
return r;
},
}
},
true =>
{
match d {
Compass::North =>
{
for i in 0..10 { r[i] = self.bitmap[0][9-i]; }
return r;
},
Compass::East =>
{
for i in 0..10 { r[i] = self.bitmap[9-i][9]; }
return r;
},
Compass::South =>
{
for i in 0..10 { r[i] = self.bitmap[9][i]; }
return r;
},
Compass::West =>
{
for i in 0..10 { r[i] = self.bitmap[i][0]; }
return r;
},
}
},
}
}
fn matching_sides(&self, tiles: &Vec<&Tile>) -> Vec<(Compass, bool)> {
let mut r = Vec::<(Compass, bool)>::new();
for d in Compass::iter() {
for f in &[true, false] {
let side = self.get_side(d, *f);
let mut c = 0;
for tile in tiles.iter().filter(|t| t.id != self.id) {
for d2 in Compass::iter() {
if side.0 == tile.get_side(d2, true).0 {
c+=1;
break;
}
}
}
if c > 0 {
r.push((d, *f))
}
}
}
return r;
}
fn gen_cache(&mut self) {
for c in Compass::iter() {
self.sides.insert((c, false), Self::side_to_int(&self.calc_side(c, false)));
self.sides.insert((c, true), Self::side_to_int(&self.calc_side(c, true)));
}
}
}
impl AdventOfCodeDay for Day20 {
fn task_1(&self) -> String {
verboseln!("{}", Day20::format_ids(&self.input));
verboseln!("{}", Day20::format_bitmaps(&self.input));
let tiles = self.input.iter().flat_map(|p| p.iter()).collect::<Vec<&Tile>>();
if is_verbose!() {
for t in tiles.iter().filter(|t| t.matching_sides(&tiles).len() == 2) {
verboseln!("{}", t.format_bitmap());
}
}
return tiles.iter().filter(|t| t.matching_sides(&tiles).len() == 2).map(|p| p.id as u128).product::<u128>().to_string();
}
fn task_2(&self) -> String {
let tiles = self.input.iter().flat_map(|p| p.iter()).collect::<Vec<&Tile>>();
let bitmap_r = Day20::reconstruct(&tiles);
verboseln!("Reconstructed:");
verboseln!("{}", Day20::format_bitmaps(&bitmap_r));
let mut bitmap_full: [[bool;8*12];8*12] = [[false;8*12];8*12];
for gy in 0..12 {
for gx in 0..12 {
for iy in 1..9 {
for ix in 1..9 {
bitmap_full[gy*8+iy-1][gx*8+ix-1] = bitmap_r[gy][gx].bitmap[iy][ix];
}
}
}
}
if is_verbose!() {
verboseln!("Raw:");
let mut ostr = String::with_capacity(8*12*8*12);
for y in 0..(8*12) {
for x in 0..(8*12) {
ostr.push(if bitmap_full[y][x] {'#'} else {'.'})
}
ostr.push('\n');
}
verboseln!("{}", ostr);
}
let monster_blueprint = "".to_owned() +
" # " + "\n" +
"# ## ## ###" + "\n" +
" # # # # # # ";
let mut monster_parts = Vec::new();
let mut monster_bitmap: [[bool;8*12];8*12] = [[false;8*12];8*12];
for tf in Transform::iter() {
let bitmap_tf = Tile::apply_transform_96(&bitmap_full, tf);
let (monsters, markers) = Day20::find_monsters(&bitmap_tf, monster_blueprint.clone());
verboseln!("Monsters in {:?}: {:?}", tf, monsters);
if !monsters.is_empty() {
monster_parts = markers;
monster_bitmap = bitmap_tf;
}
}
let mut roughness = 0;
for x in 0..(8*12) {
for y in 0..(8*12) {
if monster_bitmap[y][x] && !monster_parts.contains(&(x,y)) { roughness += 1; }
}
}
if is_verbose!() {
verboseln!("Analyzed:");
let mut ostr = String::with_capacity(8*12*8*12);
for y in 0..(8*12) {
for x in 0..(8*12) {
if monster_parts.contains(&(x,y)) {
ostr.push('O')
} else {
ostr.push(if monster_bitmap[y][x] {'#'} else {'.'})
}
}
ostr.push('\n');
}
verboseln!("{}", ostr);
}
return roughness.to_string();
}
}