Day 11 solution

Author: mbrickerd

solutions/day11.py

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+from collections import Counter
+from typing import List
+
+from aoc.models.base import SolutionBase
+
+
+class Solution(SolutionBase):
+    """Solution for Advent of Code 2024 - Day 11: Plutonian Pebbles.
+
+    This class solves a puzzle involving transforming sequences of numbers (stones)
+    according to specific rules over multiple iterations (blinks). Each stone undergoes
+    one of three transformations based on its characteristics: conversion to 1 if it's
+    a single zero, splitting in half if even-length, or multiplication by 2024 if odd-length.
+
+    Input format:
+        List containing a single string of space-separated numbers representing the initial
+        stone values. Each value is a non-negative integer represented as a string.
+
+    This class inherits from `SolutionBase` and provides methods to process stone
+    transformations and calculate the total number of stones after a specified number
+    of iterations.
+    """
+
+    def split_stones(self, stones_data: str, total_blinks: int) -> int:
+        """Process stones through multiple iterations of transformations.
+
+        Each stone undergoes one of three transformations in each blink:
+        1. If stone is "0", it becomes "1"
+        2. If stone length is even, split into two equal parts (removing leading zeros)
+        3. If stone length is odd, multiply by 2024
+
+        Args:
+            stones_data (str): Space-separated string of initial stone values
+            total_blinks (int): Number of transformation iterations to perform
+
+        Returns:
+            int: Total number of stones after all transformations are complete
+        """
+        stones = Counter(stones_data.split())
+        blinks = 1
+
+        while blinks <= total_blinks:
+            new_stones = Counter()
+            for stone, count in stones.items():
+                if len(stone) == 1 and stone == "0":
+                    new_stones["1"] += count
+
+                elif len(stone) % 2 == 0:
+                    midpoint = len(stone) // 2
+                    left = str(int(stone[:midpoint])) if stone[:midpoint] else "0"
+                    right = str(int(stone[midpoint:])) if stone[midpoint:] else "0"
+
+                    new_stones[left] += count
+                    new_stones[right] += count
+
+                else:
+                    new_stones[str(int(stone) * 2024)] += count
+
+            stones = new_stones
+            blinks += 1
+
+        return sum(stones.values())
+
+    def part1(self, data: List[str]) -> int:
+        """Calculate total stones after 25 blinks of transformations.
+
+        Args:
+            data (List[str]): Input lines containing the initial stone values
+
+        Returns:
+            int: Total number of stones after 25 transformation iterations
+        """
+        return self.split_stones(data[0], 25)
+
+    def part2(self, data: List[str]) -> int:
+        """Calculate total stones after 75 blinks of transformations.
+
+        Args:
+            data (List[str]): Input lines containing the initial stone values
+
+        Returns:
+            int: Total number of stones after 75 transformation iterations
+        """
+        return self.split_stones(data[0], 75)

tests/data/day11/test_01_input.txt

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+125 17

tests/test_11.py

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+from aoc.models.tester import TestSolutionUtility
+
+
+def test_day11_part1():
+    TestSolutionUtility.run_test(
+        day=11,
+        is_raw=False,
+        part_num=1,
+        expected=55312,
+    )