day 15

day15/i2.txt

@@ -0,0 +1,9 @@
+#######
+#...#.#
+#.....#
+#.@OO.#
+#..O..#
+#.....#
+#######
+
+>>>>>

day15/part1.py

@@ -0,0 +1,87 @@
+from __future__ import annotations
+
+import argparse
+import os.path
+
+import pytest
+
+import support
+
+INPUT_TXT = os.path.join(os.path.dirname(__file__), 'input.txt')
+
+
+def compute(s: str) -> int:
+    map_s, moves_s = s.split('\n\n')
+    walls = support.parse_coords_hash(map_s)
+    boxes = support.parse_coords_hash(map_s, wall='O')
+    bot, = support.parse_coords_hash(map_s, wall='@')
+
+    moves_s = ''.join(moves_s.split())
+    for c in moves_s:
+        d = support.Direction4.from_c(c)
+
+        boxes_to_move = set()
+        pos = d.apply(*bot)
+        while pos in boxes:
+            boxes_to_move.add(pos)
+            pos = d.apply(*pos)
+
+        if pos in walls:
+            continue
+
+        bot = d.apply(*bot)
+        boxes -= boxes_to_move
+        boxes |= {d.apply(*box) for box in boxes_to_move}
+
+    return sum(100 * y + x for x, y in boxes)
+
+
+INPUT_S = '''\
+##########
+#..O..O.O#
+#......O.#
+#.OO..O.O#
+#[email protected].#
+#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^<<^
+'''
+EXPECTED = 10092
+
+
+@pytest.mark.parametrize(
+    ('input_s', 'expected'),
+    (
+        (INPUT_S, EXPECTED),
+    ),
+)
+def test(input_s: str, expected: int) -> None:
+    assert compute(input_s) == expected
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser()
+    parser.add_argument('data_file', nargs='?', default=INPUT_TXT)
+    args = parser.parse_args()
+
+    with open(args.data_file) as f, support.timing():
+        print(compute(f.read()))
+
+    return 0
+
+
+if __name__ == '__main__':
+    raise SystemExit(main())

day15/part2.py

@@ -0,0 +1,142 @@
+from __future__ import annotations
+
+import argparse
+import os.path
+
+import pytest
+
+import support
+
+INPUT_TXT = os.path.join(os.path.dirname(__file__), 'input.txt')
+
+
+def compute(s: str) -> int:
+    map_s, moves_s = s.split('\n\n')
+    map_s = map_s.translate({
+        ord('#'): '##',
+        ord('.'): '..',
+        ord('O'): '[]',
+        ord('@'): '@.',
+    })
+    walls = support.parse_coords_hash(map_s)
+    boxes = support.parse_coords_hash(map_s, wall='[')
+    bot, = support.parse_coords_hash(map_s, wall='@')
+
+    def _boxes_to_move(d: support.Direction4) -> set[tuple[int, int]]:
+        boxes_to_move: set[tuple[int, int]] = set()
+        if d is support.Direction4.LEFT:
+            pos = d.apply(*bot)
+            if pos in walls:
+                return boxes_to_move
+            pos = d.apply(*pos)
+            while pos in boxes:
+                boxes_to_move.add(pos)
+                pos = d.apply(*pos)
+                if pos in walls:
+                    return boxes_to_move
+                pos = d.apply(*pos)
+            return boxes_to_move
+        elif d is support.Direction4.RIGHT:
+            pos = d.apply(*bot)
+            while pos in boxes:
+                boxes_to_move.add(pos)
+                pos = d.apply(*d.apply(*pos))
+            return boxes_to_move
+        elif d is support.Direction4.UP or d is support.Direction4.DOWN:
+            pos1 = d.apply(*bot)
+            pos2 = support.Direction4.LEFT.apply(*pos1)
+            layer = {pos1, pos2} & boxes
+            while layer:
+                boxes_to_move.update(layer)
+                newlayer: set[tuple[int, int]] = set()
+                for box in layer:
+                    pos1 = d.apply(*box)
+                    pos2 = support.Direction4.LEFT.apply(*pos1)
+                    pos3 = support.Direction4.RIGHT.apply(*pos1)
+                    newlayer.update((pos1, pos2, pos3))
+                layer = newlayer & boxes
+            return boxes_to_move
+        else:
+            raise AssertionError('unreachable')
+
+    def _is_box_blocked(box: tuple[int, int], d: support.Direction4) -> bool:
+        if d is support.Direction4.LEFT:
+            return d.apply(*box) in walls
+        elif d is support.Direction4.RIGHT:
+            return d.apply(*d.apply(*box)) in walls
+        elif d is support.Direction4.UP or d is support.Direction4.DOWN:
+            return (
+                d.apply(*box) in walls or
+                support.Direction4.RIGHT.apply(*d.apply(*box)) in walls
+            )
+        else:
+            raise AssertionError('unreachable')
+
+    moves_s = ''.join(moves_s.split())
+    for c in moves_s:
+        d = support.Direction4.from_c(c)
+
+        if d.apply(*bot) in walls:
+            continue
+
+        boxes_to_move = _boxes_to_move(d)
+
+        if any(_is_box_blocked(box, d) for box in boxes_to_move):
+            continue
+
+        bot = d.apply(*bot)
+        boxes -= boxes_to_move
+        boxes |= {d.apply(*box) for box in boxes_to_move}
+
+    return sum(100 * y + x for x, y in boxes)
+
+
+INPUT_S = '''\
+##########
+#..O..O.O#
+#......O.#
+#.OO..O.O#
+#[email protected].#
+#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^<<^
+'''
+EXPECTED = 9021
+
+
+@pytest.mark.parametrize(
+    ('input_s', 'expected'),
+    (
+        (INPUT_S, EXPECTED),
+    ),
+)
+def test(input_s: str, expected: int) -> None:
+    assert compute(input_s) == expected
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser()
+    parser.add_argument('data_file', nargs='?', default=INPUT_TXT)
+    args = parser.parse_args()
+
+    with open(args.data_file) as f, support.timing():
+        print(compute(f.read()))
+
+    return 0
+
+
+if __name__ == '__main__':
+    raise SystemExit(main())

support-src/support.py

@@ -183,13 +183,13 @@ def parse_coords_int(s: str) -> dict[tuple[int, int], int]:
     return coords
 
 
-def parse_coords_hash(s: str) -> set[tuple[int, int]]:
-    coords = set()
-    for y, line in enumerate(s.splitlines()):
-        for x, c in enumerate(line):
-            if c == '#':
-                coords.add((x, y))
-    return coords
+def parse_coords_hash(s: str, *, wall: str = '#') -> set[tuple[int, int]]:
+    return {
+        (x, y)
+        for y, line in enumerate(s.splitlines())
+        for x, c in enumerate(line)
+        if c == wall
+    }
 
 
 def parse_numbers_split(s: str) -> list[int]:
@@ -261,3 +261,15 @@ def opposite(self) -> Direction4:
 
     def apply(self, x: int, y: int, *, n: int = 1) -> tuple[int, int]:
         return self.x * n + x, self.y * n + y
+
+    @staticmethod
+    def from_c(c: str) -> Direction4:
+        return _DIRECTION4_C[c]
+
+
+_DIRECTION4_C = {
+    '<': Direction4.LEFT,
+    '>': Direction4.RIGHT,
+    '^': Direction4.UP,
+    'v': Direction4.DOWN,
+}