Day 11 - Puzzle 1

Author: ariejan

lib/input/day_11.txt

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+3028 78 973951 5146801 5 0 23533 857

lib/solutions/day_11.rb

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+class Day11
+  attr_accessor :stones, :blinks
+
+  def part_one(input)
+    @stones = input.split(' ').map(&:to_i)
+
+    25.times { blink! }
+
+    @stones.size
+  end
+
+  def blink!
+    new_stones = []
+    @stones.each_with_index do |stone, i|
+      value_s = stone.to_s
+
+      if stone == 0
+        new_stones[i] = 1
+      elsif value_s.length.even?
+        split = value_s.length / 2
+        new_stones[i] = [value_s[0...split].to_i, value_s[split..-1].to_i]
+      else
+        new_stones[i] = stone * 2024
+      end
+    end
+    
+    @stones = new_stones.flatten!
+  end
+
+  def part_two(input)
+    @stones = input.split(' ').map(&:to_i)
+
+    75.times { blink! }
+
+    @stones.size
+  end
+end

spec/input/day_11_test.txt

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+125 17

spec/solutions/day_11_spec.rb

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+require 'spec_helper'
+require 'solutions/day_11'
+
+RSpec.describe Day11 do
+  let(:input) { File.read(File.join(__dir__, '..', '..', 'spec', 'input', 'day_11_test.txt')).strip }
+
+  describe '#part_one' do
+    it 'calculates the correct solutions for part one' do
+      expect(subject.part_one(input)).to eq(55_312)
+    end
+  end
+
+  describe '#part_two' do
+    it 'calculates the correct solutions for part two' do
+      expect(subject.part_two(input)).to eq(0)
+    end
+  end
+end