2024 day 11.

src/holt59/aoc/2024/day11.py

@@ -1,7 +1,29 @@
+from functools import cache
 from typing import Any, Iterator
 
 from ..base import BaseSolver
 
 
+@cache
+def blink_one_stone(stone: int, round: int) -> int:
+    if round == 0:
+        return 1
+
+    if stone == 0:
+        return blink_one_stone(1, round - 1)
+
+    if len((stone_s := str(stone))) % 2 == 0:
+        n = len(stone_s)
+        return blink_one_stone(int(stone_s[: n // 2]), round - 1) + blink_one_stone(
+            int(stone_s[n // 2 :]), round - 1
+        )
+
+    return blink_one_stone(stone * 2024, round - 1)
+
+
 class Solver(BaseSolver):
-    def solve(self, input: str) -> Iterator[Any]: ...
+    def solve(self, input: str) -> Iterator[Any]:
+        stones = list(map(int, input.split()))
+
+        yield sum(blink_one_stone(stone, 25) for stone in stones)
+        yield sum(blink_one_stone(stone, 75) for stone in stones)

src/holt59/aoc/inputs/holt59/2024/day11.txt

@@ -0,0 +1 @@
+2 77706 5847 9258441 0 741 883933 12

src/holt59/aoc/inputs/tests/2024/day11.txt

@@ -0,0 +1 @@
+125 17