From 8481a5007c415e5549c173c52faec3702ab6fdc4 Mon Sep 17 00:00:00 2001
From: Reiner Herrmann <reiner@reiner-h.de>
Date: Thu, 19 Dec 2024 11:38:44 +0100
Subject: day15 solution 1

---
 src/bin/day15.rs | 198 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 198 insertions(+)
 create mode 100644 src/bin/day15.rs

(limited to 'src')

diff --git a/src/bin/day15.rs b/src/bin/day15.rs
new file mode 100644
index 0000000..c55a3f1
--- /dev/null
+++ b/src/bin/day15.rs
@@ -0,0 +1,198 @@
+use std::collections::HashSet;
+
+static DAY: u8 = 15;
+
+fn main() {
+    let input = advent::read_lines(DAY);
+    println!("{DAY}a: {}", box_coordinates(&input));
+    println!("{DAY}b: {}", 0);
+}
+
+#[derive(Eq, PartialEq, Hash, Clone, Copy)]
+struct Position {
+    x: isize,
+    y: isize,
+}
+
+impl Position {
+    fn next(&self, direction: Direction) -> Position {
+        let (x, y) = match direction {
+            Direction::Up => (self.x, self.y - 1),
+            Direction::Down => (self.x, self.y + 1),
+            Direction::Left => (self.x - 1, self.y),
+            Direction::Right => (self.x + 1, self.y),
+        };
+        Position { x, y }
+    }
+}
+
+#[derive(Clone, Copy)]
+enum Direction {
+    Up,
+    Down,
+    Left,
+    Right,
+}
+
+impl Direction {
+    fn new(input: char) -> Direction {
+        match input {
+            '^' => Direction::Up,
+            'v' => Direction::Down,
+            '<' => Direction::Left,
+            '>' => Direction::Right,
+            _ => unimplemented!(),
+        }
+    }
+}
+
+struct Map {
+    floor: HashSet<Position>,
+    boxes: HashSet<Position>,
+    robot: Position,
+    directions: Vec<Direction>,
+}
+
+impl Map {
+    fn new(input: &[String]) -> Map {
+        let mut floor = HashSet::new();
+        let mut boxes = HashSet::new();
+        let mut robot = Position { x: 0, y: 0 };
+        let mut split_line = 0;
+        for (y, line) in input.iter().enumerate() {
+            if line.is_empty() {
+                split_line = y;
+                break;
+            }
+            for (x, c) in line.chars().enumerate() {
+                let pos = Position { x: x as isize, y: y as isize };
+                match c {
+                    '.' => {
+                        floor.insert(pos);
+                    },
+                    'O' => {
+                        floor.insert(pos);
+                        boxes.insert(pos);
+                    },
+                    '@' => {
+                        floor.insert(pos);
+                        robot = pos;
+                    },
+                    _ => {}
+                }
+            }
+        }
+        let mut directions = Vec::new();
+        for line in input.iter().skip(split_line) {
+            for direction in line.chars().map(Direction::new) {
+                directions.push(direction);
+            }
+        }
+        Map { floor, boxes, robot, directions }
+    }
+
+    fn _print_map(&self) {
+        let max_x = self.floor.iter().map(|pos| pos.x).max().unwrap();
+        let max_y = self.floor.iter().map(|pos| pos.y).max().unwrap();
+        for y in 0 ..= max_y {
+            for x in 0 ..= max_x {
+                let pos = Position { x, y };
+                if self.robot == pos {
+                    print!("@");
+                } else if self.boxes.contains(&pos) {
+                    print!("O");
+                } else if self.floor.contains(&pos) {
+                    print!(".");
+                } else {
+                    print!("#");
+                }
+            }
+            println!();
+        }
+        println!();
+    }
+
+    fn coordinates(&self) -> isize {
+        self.boxes.iter()
+                  .map(|pos| pos.y * 100 + pos.x)
+                  .sum()
+    }
+
+    fn move_to(&mut self, pos: &Position, direction: Direction) -> bool {
+        if !self.floor.contains(pos) {
+            return false;
+        }
+        if self.boxes.contains(pos) {
+            let next_pos = pos.next(direction);
+            if self.move_to(&next_pos, direction) {
+                self.boxes.remove(pos);
+                self.boxes.insert(next_pos);
+            } else {
+                return false;
+            }
+        }
+        true
+    }
+
+    fn move_robot(&mut self) {
+        for direction in self.directions.clone().iter() {
+            let next_pos = self.robot.next(*direction);
+            if self.move_to(&next_pos, *direction) {
+                self.robot = next_pos;
+            }
+        }
+    }
+}
+
+fn box_coordinates(input: &[String]) -> isize {
+    let mut map = Map::new(input);
+    map.move_robot();
+    map.coordinates()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test() {
+        let input = [
+            "########",
+            "#..O.O.#",
+            "##@.O..#",
+            "#...O..#",
+            "#.#.O..#",
+            "#...O..#",
+            "#......#",
+            "########",
+            "",
+            "<^^>>>vv<v>>v<<",
+        ].iter().map(|&x| String::from(x)).collect::<Vec<_>>();
+        assert_eq!(box_coordinates(&input), 2028);
+
+        let input = [
+             "##########",
+             "#..O..O.O#",
+             "#......O.#",
+             "#.OO..O.O#",
+             "#..O@..O.#",
+             "#O#..O...#",
+             "#O..O..O.#",
+             "#.OO.O.OO#",
+             "#....O...#",
+             "##########",
+             "",
+             "<vv>^<v^>v>^vv^v>v<>v^v<v<^vv<<<^><<><>>v<vvv<>^v^>^<<<><<v<<<v^vv^v>^",
+             "vvv<<^>^v^^><<>>><>^<<><^vv^^<>vvv<>><^^v>^>vv<>v<<<<v<^v>^<^^>>>^<v<v",
+             "><>vv>v^v^<>><>>>><^^>vv>v<^^^>>v^v^<^^>v^^>v^<^v>v<>>v^v^<v>v^^<^^vv<",
+             "<<v<^>>^^^^>>>v^<>vvv^><v<<<>^^^vv^<vvv>^>v<^^^^v<>^>vvvv><>>v^<<^^^^^",
+             "^><^><>>><>^^<<^^v>>><^<v>^<vv>>v>>>^v><>^v><<<<v>>v<v<v>vvv>^<><<>^><",
+             "^>><>^v<><^vvv<^^<><v<<<<<><^v<<<><<<^^<v<^^^><^>>^<v^><<<^>>^v<v^v<v^",
+             ">^>>^v>vv>^<<^v<>><<><<v<<v><>v<^vv<<<>^^v^>^^>>><<^v>>v^v><^^>>^<>vv^",
+             "<><^^>^^^<><vvvvv^v<v<<>^v<v>v<<^><<><<><<<^^<<<^<<>><<><^^^>^^<>^>v<>",
+             "^^>vv<^v^v<vv>^<><v<^v>^^^>>>^^vvv^>vvv<>>>^<^>>>>>^<<^v>^vvv<>^<><<v>",
+             "v^^>>><<^^<>>^v^<v^vv<>v^<<>^<^v^v><^<<<><<^<v><v<>vv>>v><v^<vv<>v^<<^",
+        ].iter().map(|&x| String::from(x)).collect::<Vec<_>>();
+        assert_eq!(box_coordinates(&input), 10092);
+    }
+}
-- 
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