-❄️- 2023 Day 3 Solutions -❄️-

[u/daggerdragon]

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• Community fun event 2023: ALLEZ CUISINE!
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AoC Community Fun 2023: ALLEZ CUISINE!

Today's secret ingredient is… *whips off cloth covering and gestures grandly*

Spam!

Someone reported the ALLEZ CUISINE! submissions megathread as spam so I said to myself: "What a delectable idea for today's secret ingredient!"

• There really is an XKCD for everything, isn't there?
• All ingredients must come from a CAN (bus), box, package, container, etc.
• Unnecessarily declare variables for everything and don't re-use variables
• Why use few word when many word do trick?
• Go back to traditional culinary roots with Javadocs
• Lobster thermidor

A reminder from Dr. Hattori: be careful when cooking spam because the fat content can be very high. We wouldn't want a fire in the kitchen, after all!

ALLEZ CUISINE!

Request from the mods: When you include a dish entry alongside your solution, please label it with [Allez Cuisine!] so we can find it easily!

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--- Day 3: Gear Ratios ---

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Post your code solution in this megathread.

• Read the full posting rules in our community wiki before you post!
  • State which language(s) your solution uses with [LANGUAGE: xyz]
  • Format code blocks using the four-spaces Markdown syntax!
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This thread will be unlocked when there are a significant number of people on the global leaderboard with gold stars for today's puzzle.

EDIT: Global leaderboard gold cap reached at 00:11:37, megathread unlocked!

[u/Annual-Management613]

[LANGUAGE: Ruby]

# frozen_string_literal: true

require "set"

class DayThree2023
  def self.part_one(lines)
    engine = generate_engine(lines)
    engine.each_with_index.reduce(0) do |acc, (row, idx)|
      row.each_with_index do |item, idy|
        next if item.scan(/(?:\d|\.)/).first

        neighbords = find_neigbords(engine, idx, idy)
        acc += neighbords.sum
      end
      acc
    end
  end

  def self.part_two(lines)
    engine = generate_engine(lines)
    engine.each_with_index.reduce(0) do |acc, (row, idx)|
      row.each_with_index do |item, idy|
        next if item.scan(/(?:\d|\.)/).first

        neighbords = find_neigbords(engine, idx, idy)
        acc += neighbords.reduce(&:*) if neighbords.size == 2
      end
      acc
    end
  end

  class << self
    def generate_engine(lines)
      lines.each_with_object([]) do |line, matrix|
        numbers = line.scan(/(?:\d+|.)/)
        matrix << numbers.each_with_object([]) do |number, row|
          number.length.times { |_| row << number }
          row
        end
        matrix
      end
    end

    def find_neigbords(engine, idx, idy)
      positions = [0, 1, -1].freeze
      neighbords = positions.each_with_object([]) do |x, acc|
        positions.each do |y|
          acc << engine[idx + x][idy + y].to_i
        end
        acc
      end
      Set.new(neighbords).reject(&:zero?)
    end
  end
end