caterpillar.rb

require 'json'

class Caterpillar
  
  def pig_out(tree) 
    climb_tree(File.read(tree))
    @tree_height = @tree.length - 1
    @tree_height.downto(0) do |branch|
      (0..(branch-1)).each do |twig|
        @tree[branch - 1][twig] += [@tree[branch][twig], @tree[branch][twig+1]].max
      end
    end
    @tree[0][0]
  end
  
  def climb_tree(tree)
    @tree = JSON.parse(tree)
  end
end