SP Ruby quiz - Task 1

01_arabic_roman.rb

$map = {
	'M' 	=> 1000,
	'CM' 	=> 900,
	'D'		=> 500,
	'CD' 	=> 400,
	'C' 	=> 100,
	'XC'	=> 90,
	'L' 	=> 50,
	'XL' 	=> 40,
	'X' 	=> 10,
	'IX'	=> 9,
	'V' 	=> 5,
	'IV' 	=> 4,
	'I' 	=> 1	
}

def is_int?(s)	
	s =~ /^-?[0-9]+$/
end
	
def to_arabic(s)
	output = 0
	$map.each do |k, v| 
		while s.start_with?(k)
			output += v
			s.slice!(k)
		end
	end
	return output
end

def to_roman(i)
	output = ""	
	$map.each do |k, v| 
		while i >= v
			output << k
			i -= v
		end
	end
	return output
end

while input = gets
	if is_int?(input)
		puts to_roman(input.to_i)
	else
		puts to_arabic(input)
	end
end

Nice one! Hard-coding the combinations seems to save a lot of code ...