gistfile1.txt

class Cell
	def initialize
		@possible = (1..9).to_a
	end
	
	def cant_be(value)
		@possible = @possible - [value]
	end
	
	def must_be(value)
		@possible = [value]
	end
	
	def solved?
		@possible.size == 1
	end
	
	def can_be
		@possbile
	end
	
	def value
		@possible.first if solved?
	end
end