day 23 finished

data/day23/example01.txt

@@ -0,0 +1,7 @@
+....#..
+..###.#
+#...#.#
+.#...##
+#.###..
+##.#.##
+.#..#..

data/day23/example02.txt

@@ -0,0 +1,6 @@
+.....
+..##.
+..#..
+.....
+..##.
+.....

data/day23/input.txt

@@ -0,0 +1,70 @@
+###.###..#.....#..#.##..##.#...###.#####..#.##.#####.###..######.#.#.#
+....##.#.#.#......#.###..##..###...#.#...####.##...#.#....#.##.##....#
+#..#.#.#.##.........#####....#..##.......#.#.#.##....#.#....##..##..##
+#.##.##....#.##.#.###.#...#..#.##.####.#.#.#.#.###.###.####....#.#.#.#
+.#.#.#####.##...##.##..#..#.#..####.#..#.#.#######..#.##.#.###.#.....#
+..#..#....###.#....###.##.#..#..#.#..#.#.#...##...#....##....#..##...#
+###..........#..#.###....##.##...#####.###.#.##...#.##.....#.##.#.####
+#.###.####...#..#.##.....#.####.##..##...#..##.....#...###..##.######.
+.....#.####..##.#...#..##.###..#.##.####..#...#.###..##..#.#.###...#.#
+.#.#.#..##.##..#.#.##.#.##.#.##..##.##.#..##.#.##..#####.#.###.#.##..#
+###.#.###.##.##....#.#.#...##...#.#..#.#..#.#..##.#....#####...#...###
+.#.#.#.#.#..#....###.#.##.#.#.####..#.#.#...#.#.#.###....#....#...##..
+#.#....#........#....######...#....#..#.###...#.....###..###...##..#..
+.###.##....#.#.#.###..###....#.#.#..###.##..#..#..#####.#.###.#..##..#
+..###.##..####.....#...##.#....#...###..#.###.#...##....####........#.
+#####.##..#..##..###....#.##....#.#...##.########...#.#.#..##..##..###
+.##..#...##.....###.#...#..###.######.#.#...#...##..#.....#..#.##..#.#
+.#####..#.######.#..#..#.#.#.##....##..#.......#....#.##.#.#..##...#.#
+.#.##..#..###..#.######........##.##.##..#....#.###.######.##.#.#..##.
+##.##.#..####.#....###.#..##..#...#.#####.#..#...#....##...#.###..#.##
+#....##..#...#.#.###.#.#...##.#.#..###...####..##.#..##.#.#####.....##
+.##.#..#.##.##.#.##.....#######..#...#.##.####...#.....#.##..#...##...
+#.#.#.#####...#####..#.##....#.#.####.#..#.##..#.#.#...#..##.#...##...
+#.#.#.#..#.#.#..#..###.#.....#.#.#..#.#####.#.#..#...#.###.###...#.#..
+.####..####.#.#..#...##.##.#....#.#.....#.##.###..#...###.###.#....##.
+....##.#.##.###.#..##.#..#.......##...#.###...#.......#..####.#.#.####
+....#.#......####..#.#..#..#..#.##..#..#..###..#.#.##.#.##..###..#..#.
+.##.#.....##.#..#..#..####..#.#.#...###.##.##.##...#..##..##.##...##..
+#..####..#...#.#....##...##..#.....##.#######..#.####...##..######.#..
+..#.##.##....##.#######..##...#..#..###.....##.#.#..#.#...##..###.####
+#####......##..#.#..#......#..####.####...#####..######...##.###..##..
+###..##.#.##....##..######.#.#.#......#..##.#.##.#.##...#.##...###..##
+.....#.#.#.##..#.#####.##.#.#.....#.#..#.###.##..#.###.##..##.###....#
+.###.####..####.###....####.#.##..##..#.....##.###.##.######.#..#.#...
+.#.#######.#.#.###....#####..#.#.#..#.#.#.#.#..##..#..#...##..##..#.#.
+.##..####..#.#...###.#...#....####...###.#..#.#.....#.#.##.#..##.#.#..
+.#.#.#.#####..##.####..#..##......#..#.###.#..#....#...#....#...#.####
+..##.##.###.#..#..#.#..#.###......##.#..#..#.#.####.#.#.#.####.##.....
+##.#..#..##.#######..#..#....##..#...########.##.#.#...##...##.##.....
+.#...#####.#..##.##.###.####.....###.#......########.#..##.##.#....###
+...####.###....##..#..#....#..##.####..##..#..###.......#.#.###.##...#
+.#.#......#####...##....#.#..#######.######.#.#.##.#..###..#....##..#.
+..###.#.#####..##.#.####....#.###..#..#.##.#####.##..##.##..##..#.##.#
+.####.#.######.###.###..#......#...#...#..#..##.###.##.#.####.#.#.##.#
+#####.###.##.#########..###..#.#.##.#..#..##...#.###.#.#......###..##.
+###...###.##.#.###.#.##.####.#######..##.#....#####.###.#..#.#...###..
+.######...#...#..###......#.#.##........#..##.#.#.##.#....###.....##.#
+#.#.....##.##.##..##..##.#.##.###.##.###.##.#.##.###....##..#.#.##....
+#.####.##...##....#.#.....#.#.###..#..####.....#.##..##...##.###.#..##
+#####.##.#...#....#..###.##..##...#....#....##.#.#....#####....####.##
+####...##...#.###.##.##.#####...#.....##..#####...########..####......
+#.#..##.##.#.######.###.#.##.......#......####..##.#.#.#..##.###.#..#.
+#..#..########..##..#.######..#.#...#..#.#####.###.####......##..###.#
+#..#.#...#..#....#..##.##.#..###.####.###########.#..#.###.#.##.###..#
+##.#..#..#.....#.##.#..######..#..#...#.#...###.#.#.#.#.#.########...#
+..###.#.##......###..#...##......#####.#.#....####.....##.#..#.#..#.#.
+..######....#..##.#.#..#.##.#..##.##.#....##....###.#.##.##..##....###
+.#####....##....###.#.#######.....##.###.#..#.#.#..###...#.##..#..#.#.
+#..#####...#..##..#..#..#....#.##....#..##.......##..#....#.#..#.#.###
+#.#..#####...#...#...##.#....#..##.#.##....#####.....#.##.....#..#.###
+##.#.#....#...#.####....###....#...#.##...##.#....#.#.#.##......##.###
+...##.#.#..#.###..#.#...##.#...##.#...##...#..###.#.###...###..#..##.#
+.#####...#.#..###.#.##.##.#.##..##.#.#.....##....#.#..#.#.#..#####.###
+#.####.####..###......##.....#.#.....##.#..##.##.#....###.....####..##
+#..#####...#....#...###..##...###..####..####..#...#####.#####..#.###.
+####.###.###....####....##..#..####...#....###.##.#.##...##.......####
+.#.###....####..#..#.###.##.##.####..##.#..###..#..#.#.#..#..#.##..##.
+....##......####.####.######...###.....###.#.#..##.#.##.......#...#...
+##.###.##...#.....#.##.#.......####.##.###..###.#.#..#.##..#.####....#
+....#..##.#...##.##.#.#.#..#.#..#..#.####....#####..#.....#####.#.....

src/common/pos2.rs

@@ -2,7 +2,7 @@ use super::direction::Direction;
 use super::math::gcd;
 use num_traits::{CheckedAdd, CheckedSub, Float, Num, NumCast, Signed, Zero};
 use std::fmt;
-use std::ops::{Add, Div, Mul, Neg, Sub};
+use std::ops::{Add, AddAssign, Div, Mul, Neg, Sub};
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Default)]
 pub struct Pos2<T>([T; 2]);
@@ -157,7 +157,7 @@ where
     }
 }
 
-impl<'a, T, P: Into<Pos2<T>>> Add<P> for Pos2<T>
+impl<T, P: Into<Pos2<T>>> Add<P> for Pos2<T>
 where
     T: Num + Copy,
 {
@@ -168,6 +168,17 @@ where
     }
 }
 
+impl<T, P: Into<Pos2<T>>> AddAssign<P> for Pos2<T>
+where
+    T: AddAssign<T> + Copy,
+{
+    fn add_assign(&mut self, rhs: P) {
+        let rhs = rhs.into();
+        self.0[0] += rhs.0[0];
+        self.0[1] += rhs.0[1];
+    }
+}
+
 impl<T, P: Into<Pos2<T>>> Sub<P> for Pos2<T>
 where
     T: Num + Copy,

src/days/day23/mod.rs

@@ -0,0 +1,336 @@
+use super::template::{DayTrait, ResultType};
+use crate::common::{area::Area, direction::Direction, pos2::Pos2};
+use itertools::Itertools;
+use std::{collections::HashMap, str::FromStr};
+use thiserror::Error;
+
+const DAY_NUMBER: usize = 23;
+
+pub struct Day;
+
+impl DayTrait for Day {
+    fn get_day_number(&self) -> usize {
+        DAY_NUMBER
+    }
+
+    fn part1(&self, lines: &str) -> anyhow::Result<ResultType> {
+        let field: Field = lines.parse()?;
+        let elves = field.rounds(10);
+
+        Ok(ResultType::Integer(count_empty_tiles(&elves)))
+    }
+
+    fn part2(&self, lines: &str) -> anyhow::Result<ResultType> {
+        let field: Field = lines.parse()?;
+        let round = field.forever() as i64;
+        Ok(ResultType::Integer(round))
+    }
+}
+
+fn count_empty_tiles(elves: &[Pos2<i32>]) -> i64 {
+    let Some(area) = Area::from_iterator(elves.iter()) else {
+        return 0;
+    };
+
+    area.area() as i64 - elves.len() as i64
+}
+
+#[derive(Debug, Error)]
+enum FieldError {
+    #[error("Unknown Char: {0}")]
+    UnknownChar(char),
+}
+
+fn next_direction(current: Direction) -> Direction {
+    match current {
+        Direction::North => Direction::South,
+        Direction::South => Direction::West,
+        Direction::West => Direction::East,
+        Direction::East => Direction::North,
+    }
+}
+
+struct DirectionDispenser(Direction);
+
+impl DirectionDispenser {
+    fn new() -> DirectionDispenser {
+        Self(Direction::North)
+    }
+
+    fn progress(&mut self) {
+        self.0 = next_direction(self.0);
+    }
+
+    fn iter(&self) -> DispenserIterator {
+        DispenserIterator::new(self.0)
+    }
+}
+
+struct DispenserIterator {
+    start: Direction,
+    current: Option<Direction>,
+}
+
+impl DispenserIterator {
+    pub fn new(start: Direction) -> Self {
+        DispenserIterator {
+            start,
+            current: Some(start),
+        }
+    }
+}
+
+impl Iterator for DispenserIterator {
+    type Item = Direction;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let result = self.current;
+        if let Some(current) = self.current {
+            let next = next_direction(current);
+            if next == self.start {
+                self.current = None;
+            } else {
+                self.current = Some(next);
+            }
+        }
+        result
+    }
+}
+
+struct PosIterator {
+    pos: Pos2<i32>,
+    inc: Pos2<i32>,
+    count: usize,
+}
+
+impl PosIterator {
+    fn new(pos: Pos2<i32>, direction: Direction) -> Self {
+        let inc = direction.turn_right().into();
+        let pos = pos + direction - inc * 2;
+        Self { pos, inc, count: 0 }
+    }
+}
+
+impl Iterator for PosIterator {
+    type Item = Pos2<i32>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.count > 2 {
+            return None;
+        }
+
+        self.pos += self.inc;
+        self.count += 1;
+        Some(self.pos)
+    }
+}
+
+enum MoveCheck {
+    NoNeighbors,
+    NoFreeSpace,
+    MoveTo(Pos2<i32>, Direction),
+}
+
+struct Field {
+    direction: DirectionDispenser,
+    elves: HashMap<Pos2<i32>, bool>,
+}
+
+impl FromStr for Field {
+    type Err = FieldError;
+
+    fn from_str(lines: &str) -> Result<Self, Self::Err> {
+        let elves: HashMap<Pos2<i32>, bool> = lines
+            .split('\n')
+            .enumerate()
+            .map(|(y, row)| {
+                row.chars().enumerate().filter_map(move |(x, c)| match c {
+                    '.' => None,
+                    '#' => Some(Ok((Pos2::new(x as i32, y as i32), true))),
+                    _ => Some(Err(FieldError::UnknownChar(c))),
+                })
+            })
+            .flatten()
+            .try_collect()?;
+
+        Ok(Field {
+            direction: DirectionDispenser::new(),
+            elves,
+        })
+    }
+}
+
+impl Field {
+    fn has_neighbors(&self, pos: Pos2<i32>) -> bool {
+        for x in -1..=1 {
+            for y in -1..=1 {
+                if x != 0 || y != 0 {
+                    let check_pos = pos + (x, y);
+                    if self.elves.contains_key(&check_pos) {
+                        return true;
+                    }
+                }
+            }
+        }
+        false
+    }
+
+    fn check(&self, pos: Pos2<i32>, directions: DispenserIterator) -> MoveCheck {
+        if !self.has_neighbors(pos) {
+            return MoveCheck::NoNeighbors;
+        }
+
+        for direction in directions {
+            if self.is_empty(pos, direction) {
+                return MoveCheck::MoveTo(pos + direction, direction);
+            }
+        }
+        MoveCheck::NoFreeSpace
+    }
+
+    fn one_round(&mut self) -> bool {
+        let mut proposals: HashMap<Pos2<i32>, (Pos2<i32>, Direction)> = HashMap::new();
+        let mut deactivate = HashMap::new();
+        for elf in self
+            .elves
+            .iter()
+            .filter_map(|(elf, active)| active.then_some(*elf))
+        {
+            match self.check(elf, self.direction.iter()) {
+                MoveCheck::MoveTo(proposal, direction) => {
+                    if proposals.contains_key(&proposal) {
+                        proposals.remove(&proposal);
+                    } else {
+                        proposals.insert(proposal, (elf, direction));
+                    }
+                }
+                MoveCheck::NoNeighbors => {
+                    deactivate.insert(elf, false);
+                }
+                MoveCheck::NoFreeSpace => {}
+            }
+        }
+        if proposals.is_empty() {
+            return false;
+        }
+
+        self.elves.extend(deactivate.into_iter());
+
+        for (to, (from, direction)) in proposals {
+            self.elves.remove(&from);
+            self.elves.insert(to, true);
+            for pos in PosIterator::new(to, direction) {
+                if let Some(active) = self.elves.get_mut(&pos) {
+                    *active = true;
+                }
+            }
+        }
+        self.direction.progress();
+        true
+    }
+
+    fn is_empty(&self, pos: Pos2<i32>, direction: Direction) -> bool {
+        PosIterator::new(pos, direction).all(|pos| !self.elves.contains_key(&pos))
+    }
+
+    fn forever(mut self) -> usize {
+        for round in 0.. {
+            if !self.one_round() {
+                return round + 1;
+            }
+        }
+        unreachable!()
+    }
+
+    fn rounds(mut self, arg: usize) -> Vec<Pos2<i32>> {
+        for _ in 0..arg {
+            self.one_round();
+        }
+        self.elves.into_keys().collect_vec()
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use crate::{common::file::read_string, hashmap, hashset};
+    use anyhow::Result;
+    use std::collections::HashSet;
+
+    #[test]
+    fn test_part1() -> Result<()> {
+        let day = Day {};
+        let lines = read_string(day.get_day_number(), "example01.txt")?;
+        let expected = ResultType::Integer(110);
+        let result = day.part1(&lines)?;
+        assert_eq!(result, expected);
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_part2() -> Result<()> {
+        let day = Day {};
+        let lines = read_string(day.get_day_number(), "example01.txt")?;
+        let expected = ResultType::Integer(20);
+        let result = day.part2(&lines)?;
+        assert_eq!(result, expected);
+
+        Ok(())
+    }
+
+    #[test]
+    fn parse() -> Result<()> {
+        let day = Day {};
+        let lines = read_string(day.get_day_number(), "example02.txt")?;
+        let expected = hashmap!(
+            Pos2::new(2, 1) => true,
+            Pos2::new(3, 1) => true,
+            Pos2::new(2, 2) => true,
+            Pos2::new(2, 4) => true,
+            Pos2::new(3, 4) => true
+        );
+        let field: Field = lines.parse()?;
+        assert_eq!(field.elves, expected);
+        assert_eq!(field.direction.0, Direction::North);
+
+        Ok(())
+    }
+
+    #[test]
+    fn round1() -> Result<()> {
+        let day = Day {};
+        let lines = read_string(day.get_day_number(), "example02.txt")?;
+        let expected = hashmap!(
+            Pos2::new(2, 0) => true,
+            Pos2::new(3, 0) => true,
+            Pos2::new(2, 2) => true,
+            Pos2::new(3, 3) => true,
+            Pos2::new(2, 4) => true
+        );
+        let mut field: Field = lines.parse()?;
+        field.one_round();
+        assert_eq!(field.elves, expected);
+        assert_eq!(field.direction.0, Direction::South);
+
+        Ok(())
+    }
+
+    #[test]
+    fn round2() -> Result<()> {
+        let day = Day {};
+        let lines = read_string(day.get_day_number(), "example02.txt")?;
+        let expected = hashset!(
+            Pos2::new(2, 1),
+            Pos2::new(3, 1),
+            Pos2::new(1, 2),
+            Pos2::new(4, 3),
+            Pos2::new(2, 5)
+        );
+        let field: Field = lines.parse()?;
+        let elves = HashSet::from_iter(field.rounds(2).into_iter());
+        assert_eq!(elves, expected);
+
+        Ok(())
+    }
+}

src/days/mod.rs

@@ -20,6 +20,7 @@ mod day19;
 mod day20;
 mod day21;
 mod day22;
+mod day23;
 mod template;
 
 pub use template::DayTrait;
@@ -29,7 +30,7 @@ pub mod day_provider {
     use super::*;
     use thiserror::Error;
 
-    const MAX_DAY: usize = 22;
+    const MAX_DAY: usize = 23;
 
     pub fn get_day(day_num: usize) -> Result<Box<dyn DayTrait>, ProviderError> {
         match day_num {
@@ -55,6 +56,7 @@ pub mod day_provider {
             20 => Ok(Box::new(day20::Day)),
             21 => Ok(Box::new(day21::Day)),
             22 => Ok(Box::new(day22::Day)),
+            23 => Ok(Box::new(day23::Day)),
             _ => Err(ProviderError::InvalidNumber(day_num)),
         }
     }