Merge pull request #98 from wimglenn/2023/12

2023/12

aoc_wim/aoc2023/q12.py

@@ -0,0 +1,39 @@
+"""
+--- Day 12: Hot Springs ---
+https://adventofcode.com/2023/day/12
+"""
+from aocd import data
+from functools import cache
+
+
+@cache
+def fits(ss, cs, h=0):
+    if not any(cs):
+        return "#" not in ss
+    if not ss:
+        return 0
+    c, cs = cs[-1], cs[:-1]
+    s, ss = ss[-1], ss[:-1]
+    if not c:
+        return (s != "#") and fits(ss, cs, 0)
+    if h:
+        return (s != ".") and fits(ss, (*cs, c-1), 1)
+    if s == "#":
+        return fits(ss, (*cs, c - 1), 1)
+    if s == ".":
+        return fits(ss, (*cs, c), 0)
+    if s == "?":
+        return fits(ss, (*cs, c), 0) + fits(ss, (*cs, c - 1), 1)
+
+
+a = b = 0
+for line in data.splitlines():
+    template_a, counts = line.split()
+    counts_a = *map(int, counts.split(",")),
+    template_b = "?".join([template_a]*5)
+    counts_b = counts_a*5
+    a += fits(template_a, counts_a)
+    b += fits(template_b, counts_b)
+
+print("answer_a:", a)
+print("answer_b:", b)

tests/2023/12/0.txt

@@ -0,0 +1,8 @@
+???.### 1,1,3
+.??..??...?##. 1,1,3
+?#?#?#?#?#?#?#? 1,3,1,6
+????.#...#... 4,1,1
+????.######..#####. 1,6,5
+?###???????? 3,2,1
+21
+525152