much better

This commit is contained in:
spectre 2023-12-10 21:03:30 +01:00
parent b9bc497271
commit bdab9180a2
2 changed files with 80 additions and 153 deletions

View file

@ -1,193 +1,119 @@
use std::collections::HashSet; use std::collections::HashSet;
use std::process::abort; use std::ffi::c_ushort;
use shared::{Solution, Answer}; use shared::{Solution, Answer};
pub struct Day10; pub struct Day10;
impl Solution for Day10 { impl Solution for Day10 {
fn part_1(&self, input: &str) -> Answer { fn part_1(&self, input: &str) -> Answer {
let width: i64 = input.lines().next().unwrap().len() as i64; let mut grid: Vec<Vec<char>> = input.lines().map(|x| x.chars().collect()).collect();
let grid: Vec<_> = input.lines().collect::<Vec<&str>>().join("").chars().map(Pipes::from).collect(); let full_animal = grid.iter().flatten().position(|&x| x == 'S').unwrap();
let animal = (full_animal / grid.len(), full_animal % grid.len());
let animal = grid.iter().position(|x| x == &Pipes::Animal).unwrap(); replace_animal(&mut grid, &animal);
let mut seen: HashSet<usize> = HashSet::new(); let mut pos = animal;
let mut last: Option<(usize, usize)> = None;
let mut len = 2; let mut len_of_loop = 0;
let mut current ;
if grid[animal + 1] == Pipes::Horizontal || grid[animal + 1] == Pipes::EtoS || grid[animal + 1] == Pipes::NtoE {
current = animal + 1;
} else if grid[animal - 1] == Pipes::Horizontal || grid[animal - 1] == Pipes::WtoN || grid[animal - 1] == Pipes::StoW {
current = animal - 1;
} else { current = animal + width as usize }
seen.insert(animal);
seen.insert(current);
loop { loop {
let next = traverse(&grid, current as i64, width); len_of_loop += 1;
if next.is_none() { panic!() } let tmp = pos;
let (next1, next2) = next.unwrap(); pos = traverse(&grid[pos.0][pos.1], &pos, &last);
if seen.contains(&next1) && seen.contains(&next2) { last = Some(tmp);
break;
} else if !seen.contains(&next1) { if pos == animal {break}
current = next1;
seen.insert(next1);
len += 1;
} else if !seen.contains(&next2) {
current = next2;
seen.insert(next2);
len += 1;
} else { panic!() }
} }
Answer::from(len) Answer::from(len_of_loop / 2)
} }
fn part_2(&self, input: &str) -> Answer { fn part_2(&self, input: &str) -> Answer {
let width: usize = input.lines().next().unwrap().len(); let mut grid: Vec<Vec<char>> = input.lines().map(|x| x.chars().collect()).collect();
let mut grid: Vec<_> = input.lines().collect::<Vec<&str>>().join("").chars().map(Pipes::from).collect(); let full_animal = grid.iter().flatten().position(|&x| x == 'S').unwrap();
let animal = (full_animal / grid.len(), full_animal % grid.len());
let animal = grid.iter().position(|x| x == &Pipes::Animal).unwrap(); replace_animal(&mut grid, &animal);
replace_animal(&mut grid, animal, width);
println!("{:?}", grid[animal]);
let mut seen: HashSet<usize> = HashSet::new(); let mut pos = animal;
let mut last: Option<(usize, usize)> = None;
let mut len = 2; let mut in_loop: HashSet<(usize, usize)> = HashSet::new();
let mut current ;
if grid[animal + 1] == Pipes::Horizontal || grid[animal + 1] == Pipes::EtoS || grid[animal + 1] == Pipes::NtoE {
current = animal + 1;
} else if grid[animal - 1] == Pipes::Horizontal || grid[animal - 1] == Pipes::WtoN || grid[animal - 1] == Pipes::StoW {
current = animal - 1;
} else { current = animal + width as usize }
seen.insert(animal);
seen.insert(current);
loop { loop {
let next = traverse(&grid, current as i64, width as i64); in_loop.insert(pos);
if next.is_none() { panic!() } let tmp = pos;
let (next1, next2) = next.unwrap(); pos = traverse(&grid[pos.0][pos.1], &pos, &last);
if seen.contains(&next1) && seen.contains(&next2) { last = Some(tmp);
break;
} else if !seen.contains(&next1) { if pos == animal {break}
current = next1;
seen.insert(next1);
len += 1;
} else if !seen.contains(&next2) {
current = next2;
seen.insert(next2);
} else { panic!() }
} }
let mut parity = grid.chunks(width).map(|_| [0].repeat(width)).collect::<Vec<_>>(); let mut total = 0;
for (i, line) in grid.chunks(width).enumerate() { for (i, line) in grid.iter().enumerate() {
let mut parity = 0;
for (j, letter) in line.iter().enumerate() { for (j, letter) in line.iter().enumerate() {
if seen.contains(&(width * i + j)) { if in_loop.contains(&(i, j)) {
for k in j..width { parity += modify_parity(letter)
parity[i][k] += match letter { }
Pipes::Vertical => 2, // using 2 and 1 instead of 1 and .5 for half parity, because integers else if parity % 4 != 0 {
Pipes::StoW => 1, total += 1
Pipes::NtoE => 1,
Pipes::EtoS => -1,
Pipes::WtoN => -1,
_ => 0
}
}
} }
} }
} }
for i in seen {
parity[i / width][i % width] = 0;
}
let mut enclosed = 0; Answer::from(total)
for line in parity {
enclosed += line.iter().map(|x| (x % 4 / 2)).map(i32::abs).sum::<i32>();
println!("{:?}", line);
}
Answer::from(enclosed)
} }
} }
#[derive(Debug, PartialEq, Eq)] fn traverse(pipe: &char, pos: &(usize, usize), last: &Option<(usize, usize)>) -> (usize, usize) {
enum Pipes { let (offset1, offset2) = match *pipe {
Ground, '|' => ((-1, 0), (1, 0)),
Vertical, '-' => ((0, -1), (0, 1)),
Horizontal, 'J' => ((-1, 0), (0, -1)),
WtoN, 'L' => ((-1, 0), (0, 1)),
NtoE, 'F' => ((1, 0), (0, 1)),
EtoS, '7' => ((1, 0), (0, -1)),
StoW, l => panic!("Invalid letter {l}")
Animal
}
impl From<char> for Pipes {
fn from(value: char) -> Self {
match value {
'|' => Pipes::Vertical,
'-' => Pipes::Horizontal,
'J' => Pipes::WtoN,
'L' => Pipes::NtoE,
'F' => Pipes::EtoS,
'7' => Pipes::StoW,
'.' => Pipes::Ground,
'S' => Pipes::Animal,
_ => unreachable!()
}
}
}
fn traverse(grid: &Vec<Pipes>, current: i64, width: i64) -> Option<(usize, usize)> {
let next1 = current + match grid[current as usize] {
Pipes::Vertical => -width,
Pipes::Horizontal => -1,
Pipes::WtoN => -1,
Pipes::NtoE => -width,
Pipes::EtoS => 1,
Pipes::StoW => width,
Pipes::Animal => 0,
Pipes::Ground => unreachable!()
};
let next2 = current + match grid[current as usize] {
Pipes::Vertical => width,
Pipes::Horizontal => 1,
Pipes::WtoN => -width,
Pipes::NtoE => 1,
Pipes::EtoS => width,
Pipes::StoW => -1,
Pipes::Animal => 0,
Pipes::Ground => unreachable!()
}; };
// println!("{next1}, {next2}: Current={current}, Width={width}"); let new1 = ((offset1.0 + pos.0 as i32) as usize, (offset1.1 + pos.1 as i32) as usize);
let new2 = ((offset2.0 + pos.0 as i32) as usize, (offset2.1 + pos.1 as i32) as usize);
// if next1 - current == -1 || next1 - current == width || next1 == -1 || next1 == (grid.len() as i64) { return None }; match last {
// if next2 - current == -1 || next2 - current == width || next2 == -1 || next2 == (grid.len() as i64) { return None }; None => new1,
Some(p) if p == &new1 => new2,
Some((next1 as usize, next2 as usize)) Some(p) if p == &new2 => new1,
}
fn replace_animal(grid: &mut Vec<Pipes>, animal: usize, width: usize) {
let east = grid[animal + 1] == Pipes::Horizontal || grid[animal + 1] == Pipes::WtoN || grid[animal + 1] == Pipes::StoW;
let north = grid[animal - width] == Pipes::Vertical || grid[animal - width] == Pipes::WtoN || grid[animal - width] == Pipes::NtoE;
let west = grid[animal - 1] == Pipes::Horizontal || grid[animal - 1] == Pipes::WtoN || grid[animal - 1] == Pipes::StoW;
let south = grid[animal + width] == Pipes::Vertical || grid[animal + width] == Pipes::StoW || grid[animal + width] == Pipes::EtoS;
match (east, north, south, west) {
(false, false, true, true) => grid[animal] = Pipes::StoW,
(false, true, true, false) => grid[animal] = Pipes::Vertical,
(true, true, false, false) => grid[animal] = Pipes::NtoE,
(false, true, false, true) => grid[animal] = Pipes::WtoN,
(true, false, true, false) => grid[animal] = Pipes::EtoS,
(true, false, false, true) => grid[animal] = Pipes::Horizontal,
_ => unreachable!() _ => unreachable!()
} }
} }
fn replace_animal(grid: &mut Vec<Vec<char>>, pos: &(usize, usize)) {
let left = match grid.get(pos.0) { Some(x) => x.get((pos.1 as i32 - 1) as usize), _ => None};
let right = match grid.get(pos.0) { Some(x) => x.get(pos.1 + 1), _ => None};
let top = match grid.get((pos.0 as i32 - 1) as usize) { Some(x) => x.get(pos.1), _ => None};
let bottom = match grid.get(pos.0 + 1) { Some(x) => x.get(pos.1), _ => None};
grid[pos.0][pos.1] = match (left, right, top, bottom) {
(Some(x), Some(y), _, _) if ['-', 'L', 'F'].contains(x) && ['-', 'J', '7'].contains(y) => '-',
(Some(x), _, Some(y), _) if ['-', 'L', 'F'].contains(x) && ['|', '7', 'F'].contains(y) => 'J',
(Some(x), _, _, Some(y)) if ['-', 'L', 'F'].contains(x) && ['|', 'J', 'L'].contains(y) => '7',
(_, Some(x), Some(y), _) if ['-', 'J', '7'].contains(x) && ['|', '7', 'F'].contains(y) => 'L',
(_, Some(x), _, Some(y)) if ['-', 'J', '7'].contains(x) && ['|', 'J', 'L'].contains(y) => 'F',
(_, _, Some(x), Some(y)) if ['|', '7', 'F'].contains(x) && ['|', 'J', 'L'].contains(y) => '|',
_ => unreachable!()
}
}
fn modify_parity(l: &char) -> i32 {
match l {
'|' => 2,
'L' => 1,
'J' => -1,
'F' => -1,
'7' => 1,
_ => 0
}
}

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@ -53,6 +53,7 @@ pub mod day22;
pub mod day23; pub mod day23;
pub mod day24; pub mod day24;
pub mod day25; pub mod day25;
pub mod day10;
#[test] #[test]
fn examples() { fn examples() {