Implement 2024 day 19

Author: bertptrs

2024/src/aoc/days/day19.py

@@ -0,0 +1,37 @@
+import functools
+
+from . import CombinedRunner
+
+
+def parse_input(data: str) -> tuple[tuple[str, ...], list[str]]:
+    patterns, designs = data.strip().split("\n\n")
+
+    return tuple(patterns.split(", ")), designs.split("\n")
+
+
+@functools.cache
+def is_possible(design: str, patterns: tuple[str, ...]) -> bool:
+    if not design:
+        return 1
+
+    return sum(
+        is_possible(design[len(pat) :], patterns)
+        for pat in patterns
+        if design.startswith(pat)
+    )
+
+
+class DayRunner(CombinedRunner):
+    @classmethod
+    def run_both(cls, input: str) -> int:
+        patterns, designs = parse_input(input)
+
+        possible = 0
+        ways = 0
+
+        for design in designs:
+            if (solve := is_possible(design, patterns)) > 0:
+                possible += 1
+                ways += solve
+
+        return possible, ways

2024/tests/samples/19.txt

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+r, wr, b, g, bwu, rb, gb, br
+
+brwrr
+bggr
+gbbr
+rrbgbr
+ubwu
+bwurrg
+brgr
+bbrgwb

2024/tests/test_day19.py

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+from aoc.days.day19 import DayRunner
+
+from . import get_data
+
+
+def test_sample_part1() -> None:
+    assert DayRunner.part1(get_data(19)) == 6
+
+
+def test_sample_part2() -> None:
+    assert DayRunner.part2(get_data(19)) == 16