Solve Egyptian Fractions using Fibonacci's Greedy Algorithm

EgyptianFraction.rb

class EgyptianFraction
  class ImproperFraction < StandardError; end
  
  attr_reader :converted_fractions, :original_rational, :current_rational
  
  def initialize(numerator, denominator)
    raise ImproperFraction if numerator > denominator
    @converted_fractions = []
    @original_rational = Rational(numerator, denominator)
    @current_rational = original_rational
  end
  
  def solve
    @solved ||= convert_and_record
  end
  
  def to_r
    original_rational
  end
  
  private
  
  def convert_and_record
    convert_subfractions
    converted_fractions << current_rational
  end
  
  def convert_subfractions
    until unit_fraction?
      record_fraction(largest_subfraction)
    end
  end
  
  def largest_subfraction
    Rational(1, largest_subdenominator)
  end
  
  def largest_subdenominator
    (current_rational.denominator.to_f / current_rational.numerator.to_f).ceil
  end
  
  def unit_fraction?
    current_rational.numerator == 1
  end
  
  def record_fraction(rational)
    @current_rational -= rational
    converted_fractions << rational
  end
end