Coinfactorizer

gistfile1.rb

class Coinfactorizer
  def self.change(target, domain)
    answer = {}
    answer_data = domain.elements(target).reduce({target: target, answer: {}}) do |aggregator, domain_element|
      new_target, quantity_of_element = domain.destroy_domain_element_from_total(aggregator[:target], domain_element)
      old_answer = aggregator[:answer]
      new_answer = assoc(old_answer, domain_element, quantity_of_element) if quantity_of_element > 0
      new_answer ||= old_answer
      {target: new_target, answer: new_answer}
    end
    answer_data[:answer]
  end

  def self.assoc(hash, key, value)
    hash.merge({key => value})
  end
end

class Coins
  def self.elements(_)
    [25, 10, 5, 1]
  end

  def self.stop?(total)
    total == 0
  end

  def self.destroy_domain_element_from_total(total, domain_element)
    quantity = total/domain_element
    total -= (domain_element * quantity)
    [total, quantity]
  end
end

class Primes
  def self.divides?(top, bottom)
    (top >= bottom) && (top % bottom == 0)
  end

  def self.destroy_domain_element_from_total(total, domain_element)
    count = 0
    while divides?(total, domain_element)
      total /= domain_element
      count += 1
    end
    [total, count]
  end

  def self.stop?(total)
    total == 1
  end

  def self.elements(total)
    (2..total).to_a
  end
end