Advent of Code 2024 day010.rb

day010.rb

require_relative "main"

module Day010
  INPUT = File.read("INPUT.txt")

  grid = INPUT.to_grid(cast_int: true)

  v0s = grid.each_with_object([]) { |v, h, a| a.push(v) if h == 0 }

  ##########
  # Part 1 #
  ##########

  answer1 = v0s.sum do |v|
    endpoints = []
    dfs = ->(v, h = 1) do
      endpoints.push(v) if h == 10
      grid.four(v).filter { grid.get_value(_1) == h }.each do
        dfs.call(_1, h + 1)
      end
    end

    dfs.call(v)

    endpoints.uniq.count
  end

  pp answer1

  ##########
  # Part 2 #
  ##########

  answer2 = v0s.sum do |v|
    paths = []
    dfs = ->(v, h = 1, history = []) do
      paths.push(history) if h == 10
      grid.four(v).filter { grid.get_value(_1) == h }.each do
        dfs.call(_1, h + 1, history + [_1])
      end
    end

    dfs.call(v)

    paths.uniq.count
  end

  pp answer2
end