Solution day 12 (#10)

requirements-to-freeze.txt

@@ -1,3 +1,4 @@
 advent-of-code-data
 black
-isort
+isort
+tqdm

src/2023/12/2023_12.py

@@ -0,0 +1,104 @@
+import functools
+import re
+from typing import Any, Callable, List, Tuple
+
+from tqdm import tqdm
+
+from src.utils.data import load_data
+from src.utils.submission import submit_or_print
+
+
+def parse_input(line: str, repeats: int = 1) -> Tuple[str, List[int]]:
+    spl = line.split(" ")
+    row = "?".join([spl[0]] * repeats).strip(".")
+    groups = [int(x) for x in spl[1].split(",")]
+    groups = groups * repeats
+    return row, groups
+
+
+def calc_groups(row: str) -> List[int]:
+    groups = []
+    group_len: int = 0
+    prev_char = "."
+    for r in row:
+        if r == "#":
+            group_len += 1
+        else:
+            if prev_char == "#":
+                groups.append(group_len)
+                group_len = 0
+        prev_char = r
+    if group_len > 0:
+        groups.append(group_len)
+    return groups
+
+
+def lists_to_tuples(func: Callable) -> Any:
+    @functools.wraps(func)
+    def lists_to_tuples_wrapper(*args: Any, **kwargs: Any) -> bool:
+        args = [tuple(x) if type(x) == list else x for x in args]
+        return func(*args, **kwargs)
+
+    return lists_to_tuples_wrapper
+
+
+def tuples_to_lists(func: Callable) -> Any:
+    @functools.wraps(func)
+    def lists_to_tuples_wrapper(*args: Any, **kwargs: Any) -> bool:
+        args = [list(x) if type(x) == tuple else x for x in args]
+        return func(*args, **kwargs)
+
+    return lists_to_tuples_wrapper
+
+
+@lists_to_tuples
+@functools.lru_cache(maxsize=100_000)
+@tuples_to_lists
+def arrangements(row: str, groups: List[int]) -> int:
+    row = row.lstrip(".")
+    if "?" not in row:
+        expected_groups = calc_groups(row)
+        if expected_groups != groups:
+            return 0
+        return 1
+
+    first_unk_index = row.index("?")
+    total = 0
+    for opt in [".", "#"]:
+        new_row = row[:first_unk_index] + opt + row[first_unk_index + 1 :]
+        new_row = new_row.lstrip(".")
+
+        # try dropping initial seq of hashes
+        if m := re.match(r"(#+)\.", row):
+            group_len = len(m.group(1))
+            if not groups or groups[0] != group_len:
+                continue  # not a valid solution
+            total += arrangements(new_row[group_len:], groups[1:])
+        else:
+            total += arrangements(new_row, groups)
+
+    return total
+
+
+def main(debug: bool) -> None:
+    input_data = load_data(debug)
+
+    total = 0
+    for line in tqdm(input_data.splitlines()):
+        row, groups = parse_input(line)
+        total += arrangements(row, groups)
+    result_part1 = total
+
+    total = 0
+    for line in tqdm(input_data.splitlines()):
+        row, groups = parse_input(line, 5)
+        total += arrangements(row, groups)
+    result_part2 = total
+
+    submit_or_print(result_part1, result_part2, debug)
+
+
+if __name__ == "__main__":
+    debug_mode = True
+    debug_mode = False
+    main(debug_mode)

src/2023/12/sample_input.txt

@@ -0,0 +1,3 @@
+.#?#.?.#####.? 1,1,5,1
+###.#?#.?.#####.? 3,1,1,5
+???????????? 1