Day 21

21.py

@@ -0,0 +1,51 @@
+import numpy as np
+
+with open('data/21.txt') as file:
+    mappings = dict()
+    for line in file.readlines():
+        parts = tuple(map(lambda p: np.array(list(map(lambda r: [c == '#' for c in r], p.split('/')))),
+                          line.strip().split(' => ')))
+
+        # All possible transformations of our mappings:
+        #  - 0, 90, 180 and 270 degree rotations
+        #  - vertical (up<>down) flip followed by the 4 rotations
+        #  - horizontal (left<>right) flip followed by the 4 rotations
+        # ...Some of these may be equivalent...
+        keys = [
+            *(np.rot90(parts[0], k) for k in range(3)),
+            *(np.rot90(np.flipud(parts[0]), k) for k in range(3)),
+            *(np.rot90(np.fliplr(parts[0]), k) for k in range(3)),
+        ]
+
+        for key in keys:
+            mappings[key.tobytes()] = parts[1]
+
+
+    def expand(old_grid, length, oss, nss):
+        """
+        Expands a grid by replacing all segments with their mapped versions.
+
+        :param old_grid: The grid to expand
+        :param length: The current size of the grid (length in any direction)
+        :param oss: The size of the segment to be replaced (old segment size)
+        :param nss: The size of the segment that will replace it (new segment size)
+        :return: A new grid, with each segment expanded
+        """
+        new_grid = np.empty((length // oss * nss, length // oss * nss), dtype=bool)
+        for x in range(0, length, oss):
+            for y in range(0, length, oss):
+                new_x = x // oss * nss
+                new_y = y // oss * nss
+                new_grid[new_x:new_x+nss, new_y:new_y+nss] = mappings[old_grid[x:x + oss, y:y + oss].tobytes()]
+        return new_grid
+
+
+    grid = np.array([[False, True, False], [False, False, True], [True, True, True]])
+    for i in range(18):
+        size = len(grid)
+        grid = expand(grid, size, 2, 3) if size % 2 == 0 else expand(grid, size, 3, 4)
+
+        if i == 4:
+            print(f'Part one: {sum(sum(grid))}')
+        elif i == 17:
+            print(f'Part two: {sum(sum(grid))}')

data/21.txt

@@ -0,0 +1,108 @@
+../.. => ##./##./.##
+#./.. => .../.#./##.
+##/.. => .../.##/#.#
+.#/#. => ##./#../#..
+##/#. => .##/#.#/#..
+##/## => ..#/.#./.##
+.../.../... => #.../.##./...#/#...
+#../.../... => ...#/..../..#./..##
+.#./.../... => ..../.##./###./....
+##./.../... => ###./#.##/..#./..#.
+#.#/.../... => #.../.#../#..#/..#.
+###/.../... => ..##/.##./#.../....
+.#./#../... => #.##/..../..../#.##
+##./#../... => .#.#/.#.#/##../.#..
+..#/#../... => .###/####/.###/##..
+#.#/#../... => ..../.#.#/..../####
+.##/#../... => .##./##.#/.###/#..#
+###/#../... => ####/...#/###./.###
+.../.#./... => ..##/#..#/###./###.
+#../.#./... => ###./..##/.#.#/.#.#
+.#./.#./... => ..#./..#./##.#/##..
+##./.#./... => #..#/###./..#./#.#.
+#.#/.#./... => .###/#.../.#.#/.##.
+###/.#./... => #.##/##../#.#./...#
+.#./##./... => #.##/#.##/#.##/.###
+##./##./... => ..##/#..#/.###/....
+..#/##./... => #..#/.##./##../####
+#.#/##./... => ###./###./..##/..##
+.##/##./... => ###./##.#/.##./###.
+###/##./... => ##../#..#/##../....
+.../#.#/... => ##.#/..#./..##/##..
+#../#.#/... => #..#/.###/.#../#.#.
+.#./#.#/... => ####/#.##/.###/###.
+##./#.#/... => #.../####/...#/.#.#
+#.#/#.#/... => ...#/.#.#/#..#/#.##
+###/#.#/... => ###./#.##/##.#/..##
+.../###/... => ..../##.#/.#../..##
+#../###/... => ####/..##/.##./.###
+.#./###/... => #.#./#.#./#.../#..#
+##./###/... => #..#/..##/#.##/#.#.
+#.#/###/... => .##./##.#/.#../####
+###/###/... => ####/##.#/.#../#.#.
+..#/.../#.. => #..#/#.##/.###/.###
+#.#/.../#.. => .##./#.../.#.#/....
+.##/.../#.. => .#.#/.#.#/##../####
+###/.../#.. => .#.#/.##./####/##.#
+.##/#../#.. => .###/.###/.###/#...
+###/#../#.. => ..##/#.../#.#./..#.
+..#/.#./#.. => #.#./##../##../####
+#.#/.#./#.. => ..../..##/#..#/..#.
+.##/.#./#.. => #.##/#..#/##.#/.##.
+###/.#./#.. => ...#/#.../#.#./.#..
+.##/##./#.. => .##./#..#/.##./...#
+###/##./#.. => ##.#/##.#/.##./...#
+#../..#/#.. => ##../..#./..#./#.#.
+.#./..#/#.. => #.#./##../#..#/#.##
+##./..#/#.. => #.##/###./###./.#.#
+#.#/..#/#.. => ..../...#/...#/#..#
+.##/..#/#.. => #..#/#.#./..##/.##.
+###/..#/#.. => ##../.#.#/.#../#.#.
+#../#.#/#.. => ####/.##./.##./.##.
+.#./#.#/#.. => ...#/.##./..#./.##.
+##./#.#/#.. => .#.#/.##./..#./.#.#
+..#/#.#/#.. => .#../##.#/##../#...
+#.#/#.#/#.. => .#.#/..#./#.../##..
+.##/#.#/#.. => ..#./#.#./###./#...
+###/#.#/#.. => ..../#.#./..##/##.#
+#../.##/#.. => .##./##../.#../..##
+.#./.##/#.. => ##../#.#./#.../####
+##./.##/#.. => ###./###./#.#./..##
+#.#/.##/#.. => ...#/#..#/..#./###.
+.##/.##/#.. => ..##/####/..../#.##
+###/.##/#.. => .#.#/#.../.##./#...
+#../###/#.. => ..#./.#.#/#..#/.##.
+.#./###/#.. => ####/..../####/#.##
+##./###/#.. => .###/..../#.#./####
+..#/###/#.. => ###./#.#./.#.#/#...
+#.#/###/#.. => #.#./#.#./..##/.##.
+.##/###/#.. => #.##/.###/.##./#.##
+###/###/#.. => #..#/.#../.#../.##.
+.#./#.#/.#. => .#../.##./##../..##
+##./#.#/.#. => .##./#.##/...#/#.#.
+#.#/#.#/.#. => ##.#/###./#.#./..#.
+###/#.#/.#. => ..../##../.###/###.
+.#./###/.#. => .#.#/.###/..../#..#
+##./###/.#. => #.../..#./#..#/.#..
+#.#/###/.#. => .#../##.#/##.#/.###
+###/###/.#. => #..#/.#.#/#.#./..#.
+#.#/..#/##. => .#../.###/...#/#.##
+###/..#/##. => ...#/...#/..##/...#
+.##/#.#/##. => #.#./###./.##./####
+###/#.#/##. => #.#./...#/...#/....
+#.#/.##/##. => ###./#.../##.#/..#.
+###/.##/##. => .#../#.../.###/.#..
+.##/###/##. => #.../..#./..#./.###
+###/###/##. => .#../.#../####/###.
+#.#/.../#.# => ##.#/##../...#/##.#
+###/.../#.# => ###./###./#..#/###.
+###/#../#.# => .###/..#./.#../#...
+#.#/.#./#.# => ##.#/.##./.#.#/##.#
+###/.#./#.# => ...#/...#/#.##/.##.
+###/##./#.# => #.../##../#.../....
+#.#/#.#/#.# => ####/.#../..##/..##
+###/#.#/#.# => ##../####/#.##/..##
+#.#/###/#.# => ##../..../..../####
+###/###/#.# => .#../.#.#/.###/.#.#
+###/#.#/### => ##../####/###./...#
+###/###/### => ###./#..#/##../.##.