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Diffstat (limited to 'src/2022/9/mod.rs')
| -rw-r--r-- | src/2022/9/mod.rs | 240 |
1 files changed, 240 insertions, 0 deletions
diff --git a/src/2022/9/mod.rs b/src/2022/9/mod.rs new file mode 100644 index 0000000..b4f5f0a --- /dev/null +++ b/src/2022/9/mod.rs @@ -0,0 +1,240 @@ +#![allow(dead_code)] +#![allow(unused_variables)] + +use crate::prelude::*; + +#[derive(Debug)] +enum Direction { + Up, + Down, + Left, + Right, +} + +impl std::str::FromStr for Direction { + type Err = (); + + fn from_str(s: &str) -> Result<Self, Self::Err> { + Ok(match s { + "U" => Self::Up, + "D" => Self::Down, + "L" => Self::Left, + "R" => Self::Right, + _ => return Err(()), + }) + } +} + +#[derive(Debug)] +pub struct Move { + dir: Direction, + count: usize, +} + +impl Move { + fn parse(line: &str) -> Self { + let mut parts = line.split_whitespace(); + let dir = parts.next().unwrap().parse().unwrap(); + let count = parts.next().unwrap().parse().unwrap(); + Self { dir, count } + } +} + +pub struct Rope { + knots: Vec<(Row, Col)>, +} + +impl Rope { + pub fn new(len: usize) -> Self { + Self { + knots: vec![Default::default(); len], + } + } + + pub fn at(&self, pos: (Row, Col)) -> Option<usize> { + for (i, knot) in self.knots.iter().enumerate() { + if knot == &pos { + return Some(i); + } + } + None + } +} + +pub struct Map { + grid: std::collections::VecDeque<std::collections::VecDeque<bool>>, + size: (Row, Col), + rope: Rope, +} + +impl std::fmt::Debug for Map { + fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { + writeln!(f, "({}, {})", self.size.0 .0, self.size.1 .0)?; + for row in (0..self.size.0 .0).rev() { + for col in 0..self.size.1 .0 { + write!( + f, + "{}", + if let Some(idx) = self.rope.at((Row(row), Col(col))) { + char::from(b'0' + u8::try_from(idx).unwrap()) + } else if self.grid[row][col] { + '#' + } else { + '.' + } + )?; + } + writeln!(f)?; + } + Ok(()) + } +} + +impl Map { + fn new(len: usize) -> Self { + let mut grid = std::collections::VecDeque::new(); + grid.push_back(std::collections::VecDeque::new()); + grid[0].push_back(true); + Self { + grid, + size: (Row(1), Col(1)), + rope: Rope::new(len), + } + } + + fn mv(&mut self, mv: &Move) { + // println!("{:?}", mv); + for _ in 0..mv.count { + self.step(&mv.dir); + } + } + + fn step(&mut self, dir: &Direction) { + let (Row(row), Col(col)) = self.rope.knots[0]; + match dir { + Direction::Up => { + if row == self.size.0 .0 - 1 { + let mut row_contents = std::collections::VecDeque::new(); + row_contents + .resize_with(self.size.1 .0, Default::default); + self.grid.push_back(row_contents); + self.size.0 = Row(self.size.0 .0 + 1); + } + self.rope.knots[0].0 = Row(self.rope.knots[0].0 .0 + 1); + } + Direction::Down => { + if row == 0 { + let mut row_contents = std::collections::VecDeque::new(); + row_contents + .resize_with(self.size.1 .0, Default::default); + self.grid.push_front(row_contents); + for knot in &mut self.rope.knots { + knot.0 = Row(knot.0 .0 + 1); + } + self.size.0 = Row(self.size.0 .0 + 1); + } + self.rope.knots[0].0 = Row(self.rope.knots[0].0 .0 - 1); + } + Direction::Left => { + if col == 0 { + for i in 0..self.size.0 .0 { + self.grid[i].push_front(Default::default()); + } + for knot in &mut self.rope.knots { + knot.1 = Col(knot.1 .0 + 1); + } + self.size.1 = Col(self.size.1 .0 + 1); + } + self.rope.knots[0].1 = Col(self.rope.knots[0].1 .0 - 1); + } + Direction::Right => { + if col == self.size.1 .0 - 1 { + for i in 0..self.size.0 .0 { + self.grid[i].push_back(Default::default()); + } + self.size.1 = Col(self.size.1 .0 + 1); + } + self.rope.knots[0].1 = Col(self.rope.knots[0].1 .0 + 1); + } + } + + for i in 0..(self.rope.knots.len() - 1) { + if self.rope.knots[i + 1] + .0 + .0 + .abs_diff(self.rope.knots[i].0 .0) + > 1 + || self.rope.knots[i + 1] + .1 + .0 + .abs_diff(self.rope.knots[i].1 .0) + > 1 + { + if self.rope.knots[i + 1].0 .0 < self.rope.knots[i].0 .0 { + self.rope.knots[i + 1].0 .0 += 1; + } + if self.rope.knots[i + 1].0 .0 > self.rope.knots[i].0 .0 { + self.rope.knots[i + 1].0 .0 -= 1; + } + if self.rope.knots[i + 1].1 .0 < self.rope.knots[i].1 .0 { + self.rope.knots[i + 1].1 .0 += 1; + } + if self.rope.knots[i + 1].1 .0 > self.rope.knots[i].1 .0 { + self.rope.knots[i + 1].1 .0 -= 1; + } + } + } + self.grid[self.rope.knots.last().unwrap().0 .0] + [self.rope.knots.last().unwrap().1 .0] = true; + } +} + +pub fn parse(fh: File) -> Result<impl Iterator<Item = Move>> { + Ok(parse::lines(fh).map(|line| Move::parse(&line))) +} + +pub fn part1(moves: impl Iterator<Item = Move>) -> Result<i64> { + let mut map = Map::new(2); + for mv in moves { + // println!("{:?}", map); + map.mv(&mv); + } + // println!("{:?}", map); + Ok(map + .grid + .iter() + .flat_map(|row| row.iter().copied()) + .filter(|cell| *cell) + .count() + .try_into() + .unwrap()) +} + +pub fn part2(moves: impl Iterator<Item = Move>) -> Result<i64> { + let mut map = Map::new(10); + for mv in moves { + // println!("{:?}", map); + map.mv(&mv); + } + // println!("{:?}", map); + Ok(map + .grid + .iter() + .flat_map(|row| row.iter().copied()) + .filter(|cell| *cell) + .count() + .try_into() + .unwrap()) +} + +#[test] +fn test() { + assert_eq!( + part1(parse(parse::data(2022, 9).unwrap()).unwrap()).unwrap(), + 0 + ); + assert_eq!( + part2(parse(parse::data(2022, 9).unwrap()).unwrap()).unwrap(), + 0 + ); +} |