From d4aad95f559286f3f2913187a17b18cb4f902220 Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Thu, 19 Dec 2024 09:05:55 +0100
Subject: [PATCH] Implement 2024 day 19

---
 2024/src/aoc/days/day19.py | 37 +++++++++++++++++++++++++++++++++++++
 2024/tests/samples/19.txt  | 10 ++++++++++
 2024/tests/test_day19.py   | 11 +++++++++++
 3 files changed, 58 insertions(+)
 create mode 100644 2024/src/aoc/days/day19.py
 create mode 100644 2024/tests/samples/19.txt
 create mode 100644 2024/tests/test_day19.py

diff --git a/2024/src/aoc/days/day19.py b/2024/src/aoc/days/day19.py
new file mode 100644
index 0000000..b2e9f06
--- /dev/null
+++ b/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
diff --git a/2024/tests/samples/19.txt b/2024/tests/samples/19.txt
new file mode 100644
index 0000000..29648be
--- /dev/null
+++ b/2024/tests/samples/19.txt
@@ -0,0 +1,10 @@
+r, wr, b, g, bwu, rb, gb, br
+
+brwrr
+bggr
+gbbr
+rrbgbr
+ubwu
+bwurrg
+brgr
+bbrgwb
diff --git a/2024/tests/test_day19.py b/2024/tests/test_day19.py
new file mode 100644
index 0000000..981528b
--- /dev/null
+++ b/2024/tests/test_day19.py
@@ -0,0 +1,11 @@
+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