#
# This file contains the Ruby code from Program 7.32 of
# "Data Structures and Algorithms
# with Object-Oriented Design Patterns in Ruby"
# by Bruno R. Preiss.
#
# Copyright (c) 2004 by Bruno R. Preiss, P.Eng.  All rights reserved.
#
# http://www.brpreiss.com/books/opus8/programs/pgm07_32.txt
#
class PolynomialAsSortedList < Polynomial

    def initialize
        super
        @list = SortedListAsLinkedList.new
    end

    attr_reader :list

    def +(poly)
        result = PolynomialAsSortedList.new
        p1 = @list.iter
        p2 = poly.list.iter
        term1 = p1.succ
        term2 = p2.succ
        while not term1.nil? and not term2.nil?
            if term1.exponent < term2.exponent
                result.addTerm(term1.clone)
                term1 = p1.succ
            elsif term1.exponent > term2.exponent
                result.addTerm(term2.clone)
                term2 = p2.succ
            else
                sum = term1 + term2
		result.addTerm(sum) if sum.coefficient != 0
                term1 = p1.succ
                term2 = p2.succ
	    end
	end
        while not term1.nil?
            result.addTerm(term1.clone)
	    term1 = p1.succ
	end
        while not term2.nil?
            result.addTerm(term2.clone)
	    term2 = p2.succ
	end
        return result
    end

end