2024 day 11 parts 2

README.md

@@ -15,7 +15,7 @@
 - 2021 - ★★★★★ ★★★★★ ★★★★★ ★★★
 - 2022 - ★★★★★ ★★★★★ ★★★★★ ★☆
 - 2023 - ★★★★★ ★★★★★ ★★★★★ ★★★☆
-- 2024 - ★★★★★ ★★★★★ ☆
+- 2024 - ★★★★★ ★★★★★ ★
 
 ## How to use
 

src/year2024/day11b.py

@@ -0,0 +1,26 @@
+"""2024 - Day 11 Part 2: Plutonian Pebbles"""
+
+from functools import cache
+
+
+@cache
+def evolve(stone: int, generation: int) -> int:
+    if generation == 0:
+        return 1
+
+    if stone == 0:
+        return evolve(1, generation - 1)
+    elif len(str(stone)) % 2 == 0:
+        middle = len(str(stone)) // 2
+
+        left = int(str(stone)[:middle])
+        right = int(str(stone)[middle:])
+
+        return evolve(left, generation - 1) + evolve(right, generation - 1)
+    else:
+        return evolve(stone * 2024, generation - 1)
+
+
+def solve(task: str) -> int:
+    stones = [int(x) for x in task.split()]
+    return sum(evolve(stone, 75) for stone in stones)

tests/src/year2024/test_day11b.py

@@ -0,0 +1,8 @@
+"""2024 - Day 11 Part 2: Plutonian Pebbles"""
+
+from src.year2024.day11b import solve
+
+
+def test_solve():
+    task = "125 17"
+    assert solve(task) == 65601038650482