2020 day 19 and day 20 part 1

2020/d19.py

@@ -0,0 +1,62 @@
+from lib import get_data
+
+data = get_data(__file__)
+
+rules = {}
+msgs = []
+
+for line in data.splitlines():
+    if len(line.strip()) == 0:
+        continue
+
+    if ":" in line:
+        id, rule = line.split(":")
+        id = int(id)
+
+        branches = [[]]
+        for part in rule.split():
+            if part.startswith('"') and part.endswith('"'):
+                branches = part[1]
+            elif part == "|":
+                assert type(branches) is list
+                branches.append([])
+            else:
+                assert type(branches) is list
+                branches[-1].append(int(part))
+        rules[id] = branches
+    else:
+        msgs.append(line.strip())
+
+
+def matches(xs, rule):
+    if xs == "" and rule == []:
+        return True
+    elif xs == "" or rule == []:
+        return False
+
+    current = rules[rule[0]]
+    if current == xs[0]:
+        return matches(xs[1:], rule[1:])
+    elif type(current) is str:
+        return False
+    elif len(current) >= 1:
+        for ys in current:
+            if matches(xs, ys + rule[1:]):
+                return True
+    return False
+
+
+t = 0
+for m in msgs:
+    if matches(m, rules[0][0]):
+        t += 1
+print(t)
+
+rules[8] = [[42], [42, 8]]
+rules[11] = [[42, 31], [42, 11, 31]]
+
+t = 0
+for m in msgs:
+    if matches(m, rules[0][0]):
+        t += 1
+print(t)

2020/d20.py

@@ -0,0 +1,238 @@
+from collections import defaultdict
+from lib import get_data, ints
+from math import isqrt
+
+data = """Tile 2311:
+..##.#..#.
+##..#.....
+#...##..#.
+####.#...#
+##.##.###.
+##...#.###
+.#.#.#..##
+..#....#..
+###...#.#.
+..###..###
+
+Tile 1951:
+#.##...##.
+#.####...#
+.....#..##
+#...######
+.##.#....#
+.###.#####
+###.##.##.
+.###....#.
+..#.#..#.#
+#...##.#..
+
+Tile 1171:
+####...##.
+#..##.#..#
+##.#..#.#.
+.###.####.
+..###.####
+.##....##.
+.#...####.
+#.##.####.
+####..#...
+.....##...
+
+Tile 1427:
+###.##.#..
+.#..#.##..
+.#.##.#..#
+#.#.#.##.#
+....#...##
+...##..##.
+...#.#####
+.#.####.#.
+..#..###.#
+..##.#..#.
+
+Tile 1489:
+##.#.#....
+..##...#..
+.##..##...
+..#...#...
+#####...#.
+#..#.#.#.#
+...#.#.#..
+##.#...##.
+..##.##.##
+###.##.#..
+
+Tile 2473:
+#....####.
+#..#.##...
+#.##..#...
+######.#.#
+.#...#.#.#
+.#########
+.###.#..#.
+########.#
+##...##.#.
+..###.#.#.
+
+Tile 2971:
+..#.#....#
+#...###...
+#.#.###...
+##.##..#..
+.#####..##
+.#..####.#
+#..#.#..#.
+..####.###
+..#.#.###.
+...#.#.#.#
+
+Tile 2729:
+...#.#.#.#
+####.#....
+..#.#.....
+....#..#.#
+.##..##.#.
+.#.####...
+####.#.#..
+##.####...
+##..#.##..
+#.##...##.
+
+Tile 3079:
+#.#.#####.
+.#..######
+..#.......
+######....
+####.#..#.
+.#...#.##.
+#.#####.##
+..#.###...
+..#.......
+..#.###..."""
+
+data = get_data(__file__)
+
+
+def top(rows):
+    return rows[0]
+
+
+def bottom(rows):
+    return rows[-1]
+
+
+def left(rows):
+    return [row[0] for row in rows]
+
+
+def right(rows):
+    return [row[-1] for row in rows]
+
+
+def fliph(rows):
+    return [row[::-1] for row in rows]
+
+
+def flipv(rows):
+    return rows[::-1]
+
+
+def rot90(rows):
+    return [row for row in zip(*rows[::-1])]
+
+
+def rot180(rows):
+    return rot90(rot90(rows))
+
+
+def rot270(rows):
+    return rot90(rot90(rot90(rows)))
+
+
+def get_borders(rows):
+    return tuple(top(rows)), tuple(right(rows)), tuple(bottom(rows)), tuple(left(rows))
+
+
+TOP = 0
+RIGHT = 1
+BOTTOM = 2
+LEFT = 3
+
+
+def all(rows) -> list:
+    orientations = [
+        rows,
+        rot90(rows),
+        rot180(rows),
+        rot270(rows),
+        fliph(rows),
+        flipv(rows),
+        rot90(fliph(rows)),
+        rot90(flipv(rows)),
+        rot180(fliph(rows)),
+        rot180(flipv(rows)),
+        rot270(fliph(rows)),
+        rot270(flipv(rows)),
+    ]
+    return [get_borders(orientation) for orientation in orientations]
+
+
+tiles = []
+for p in data.strip().split("\n\n"):
+    lines = p.splitlines()
+    (id,) = ints(lines[0])
+    tiles.append((id, all(lines[1:])))
+
+
+rights = defaultdict(list)
+bottoms = defaultdict(list)
+
+for id, variants in tiles:
+    for variant in variants:
+        rights[variant[LEFT]].append((id, variant))
+        bottoms[variant[TOP]].append((id, variant))
+
+num_tiles = len(tiles)
+rows = isqrt(len(tiles))
+
+
+def dfs(id_set, id_list, tiles_used):
+    if len(tiles_used) == num_tiles:
+        return id_list
+
+    i = len(tiles_used)
+    id_variants = None
+    if i < rows:  # first row
+        id_variants = rights[tiles_used[i - 1][RIGHT]]
+    elif i % rows == 0:  # first tile in row
+        id_variants = bottoms[tiles_used[i - rows][BOTTOM]]
+    else:
+        id_variants = set(bottoms[tiles_used[i - rows][BOTTOM]])
+        id_variants &= set(rights[tiles_used[i - 1][RIGHT]])
+        id_variants = list(id_variants)
+
+    assert id_variants is not None
+
+    for id, variant in id_variants:
+        if id in id_set:
+            continue
+        id_set.add(id)
+        id_list.append(id)
+        tiles_used.append(variant)
+        r = dfs(id_set, id_list, tiles_used)
+        if r is not False:
+            return r
+        tiles_used.pop()
+        id_set.remove(id)
+        id_list.pop()
+    return False
+
+
+for id, tile_variants in tiles:
+    for tile in tile_variants:
+        r = dfs(set([id]), [id], [tile])
+        if type(r) is list:
+            print(r[0] * r[-1] * r[rows - 1] * r[-rows])
+            exit(0)
+else:
+    print("no result")

README.md

@@ -157,7 +157,8 @@ Solutions and utility script for Advent of Code challenges in Python.
 - Day 16: 33:00 (Not too unhappy really.)
 - Day 17: 10:00 (40th)
 - Day 18: 80:00 (I am struggling with stuff where parsing is involved)
-- Day 19:
+- Day 19: 78:00 (Should have been faster)
+- Day 20:
 
 ## AoC 2022
 

lib.py

@@ -202,6 +202,9 @@ def str_to_ints(line: str) -> list[int]:
     return list(map(int, r.findall(line)))
 
 
+ints = str_to_ints
+
+
 def str_to_lines_no_empty(text: str) -> list[str]:
     return list(filter(lambda l: l.strip() != "", text.splitlines()))