Added solutions for day 24

askrepps · askrepps · commit 0a02cc1f2afe · 2021-11-30T22:59:30.000-05:00
diff --git a/advent2020/day24.py b/advent2020/day24.py
@@ -0,0 +1,136 @@
+# MIT License
+#
+# Copyright (c) 2021 Andrew Krepps
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+
+from enum import Enum
+
+from . import util
+
+
+class Direction(Enum):
+    EAST = 0
+    WEST = 1
+    NORTHEAST = 2
+    NORTHWEST = 3
+    SOUTHEAST = 4
+    SOUTHWEST = 5
+
+    def get_movement_amount(self):
+        if self == Direction.EAST:
+            return 2, 0
+        elif self == Direction.WEST:
+            return -2, 0
+        elif self == Direction.NORTHEAST:
+            return 1, 1
+        elif self == Direction.NORTHWEST:
+            return -1, 1
+        elif self == Direction.SOUTHEAST:
+            return 1, -1
+        elif self == Direction.SOUTHWEST:
+            return -1, -1
+        else:
+            raise ValueError(f"Unknown direction {self}")
+
+
+def extract_directions(line):
+    idx = 0
+    directions = []
+    while idx < len(line):
+        c = line[idx]
+        idx += 1
+        if c == 'e':
+            directions.append(Direction.EAST)
+        elif c == 'w':
+            directions.append(Direction.WEST)
+        else:
+            c2 = line[idx]
+            idx += 1
+            if c == 'n':
+                if c2 == 'e':
+                    directions.append(Direction.NORTHEAST)
+                elif c2 == 'w':
+                    directions.append(Direction.NORTHWEST)
+            elif c == 's':
+                if c2 == 'e':
+                    directions.append(Direction.SOUTHEAST)
+                elif c2 == 'w':
+                    directions.append(Direction.SOUTHWEST)
+    return directions
+
+
+def parse_input(lines):
+    return [extract_directions(line) for line in lines]
+
+
+def move_coordinates(coordinates, direction):
+    move_x, move_y = direction.get_movement_amount()
+    return coordinates[0] + move_x, coordinates[1] + move_y
+
+
+def initialize_tiles(direction_sets):
+    flipped_tiles = set()
+    for directions in direction_sets:
+        current_tile = (0, 0)
+        for direction in directions:
+            current_tile = move_coordinates(current_tile, direction)
+        if current_tile in flipped_tiles:
+            flipped_tiles.remove(current_tile)
+        else:
+            flipped_tiles.add(current_tile)
+    return flipped_tiles
+
+
+def get_next_tile_set(flipped_tiles):
+    flipped_neighbor_counts = {tile: 0 for tile in flipped_tiles}
+    for tile in flipped_tiles:
+        for direction in Direction:
+            neighbor = move_coordinates(tile, direction)
+            if neighbor not in flipped_neighbor_counts.keys():
+                flipped_neighbor_counts[neighbor] = 1
+            else:
+                flipped_neighbor_counts[neighbor] += 1
+
+    next_flipped_tiles = set()
+    for tile, flipped_neighbors in flipped_neighbor_counts.items():
+        if tile in flipped_tiles and not (flipped_neighbors == 0 or flipped_neighbors > 2):
+            next_flipped_tiles.add(tile)
+        elif tile not in flipped_tiles and flipped_neighbors == 2:
+            next_flipped_tiles.add(tile)
+    return next_flipped_tiles
+
+
+def get_part1_answer(flipped_tiles):
+    return len(flipped_tiles)
+
+
+def get_part2_answer(flipped_tiles):
+    for day in range(100):
+        flipped_tiles = get_next_tile_set(flipped_tiles)
+    return len(flipped_tiles)
+
+
+def run():
+    lines = util.get_input_file_lines("day24.txt")
+    directions_sets = parse_input(lines)
+    flipped_tiles = initialize_tiles(directions_sets)
+    print(f"The answer to part 1 is {get_part1_answer(flipped_tiles)}")
+    print(f"The answer to part 2 is {get_part2_answer(flipped_tiles)}")
diff --git a/main.py b/main.py
@@ -46,6 +46,7 @@
 from advent2020 import day21
 from advent2020 import day22
 from advent2020 import day23
+from advent2020 import day24
 
 
 day_runners = [
@@ -71,7 +72,8 @@
     lambda: day20.run(),
     lambda: day21.run(),
     lambda: day22.run(),
-    lambda: day23.run()
+    lambda: day23.run(),
+    lambda: day24.run()
 ]
 
 
diff --git a/test/test_day24.py b/test/test_day24.py
@@ -0,0 +1,63 @@
+# MIT License
+#
+# Copyright (c) 2021 Andrew Krepps
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+
+import unittest
+
+from advent2020.day24 import get_part1_answer
+from advent2020.day24 import get_part2_answer
+from advent2020.day24 import initialize_tiles
+from advent2020.day24 import parse_input
+from advent2020.util import get_input_data_lines
+
+
+data = """
+sesenwnenenewseeswwswswwnenewsewsw
+neeenesenwnwwswnenewnwwsewnenwseswesw
+seswneswswsenwwnwse
+nwnwneseeswswnenewneswwnewseswneseene
+swweswneswnenwsewnwneneseenw
+eesenwseswswnenwswnwnwsewwnwsene
+sewnenenenesenwsewnenwwwse
+wenwwweseeeweswwwnwwe
+wsweesenenewnwwnwsenewsenwwsesesenwne
+neeswseenwwswnwswswnw
+nenwswwsewswnenenewsenwsenwnesesenew
+enewnwewneswsewnwswenweswnenwsenwsw
+sweneswneswneneenwnewenewwneswswnese
+swwesenesewenwneswnwwneseswwne
+enesenwswwswneneswsenwnewswseenwsese
+wnwnesenesenenwwnenwsewesewsesesew
+nenewswnwewswnenesenwnesewesw
+eneswnwswnwsenenwnwnwwseeswneewsenese
+neswnwewnwnwseenwseesewsenwsweewe
+wseweeenwnesenwwwswnew
+"""
+
+
+class Day24Test(unittest.TestCase):
+    def test_day24(self):
+        lines = get_input_data_lines(data)
+        directions_sets = parse_input(lines)
+        flipped_tiles = initialize_tiles(directions_sets)
+        self.assertEqual(get_part1_answer(flipped_tiles), 10)
+        self.assertEqual(get_part2_answer(flipped_tiles), 2208)
