inside_cyclic.rb given a directed or undirected graph check if given element is in a cyclic structure

inside_cyclic.rb

=begin 
:mat utter, 10/18/2014
=end
class Graph
	def initialize()
		@graph = Hash.new(false)
		@visit = Hash.new(false)
		@target = false
	end
	def add(key,val)
		@visit	[key] = false

		if @graph.has_key?(key) 
			@graph[key].push( val )
		else
			@graph[key] = Array.new
			@graph[key].push( val )
		end
		# for directed graphs comment below out		
		if @graph.has_key?(val) 
			@graph[val].push( key )
		else
			@graph[val] = Array.new
			@graph[val].push( key )
		end
		@graph[val].uniq!
		@graph[key].uniq!
	end

	def delete(u,v)
		@graph[u].delete_if { |x| x == v }
		@graph[v].delete_if { |x| x == u }
	end

	def to_s
		return "#{@graph}\n#{@visit}"
	end
	def Next # gets next unvisited
	end
	def G
		@graph
	end
	#cycle part
	def in_cycle(u,v)
		self.delete(u,v)
		puts "Goal = #{v}"
		@visit[u] = true
		return self._check_cycle(u, v) 
	end

	def _check_cycle(u,v)
		@graph[u].each do | val |
			next if @visit[val]
			puts "#{u} -> #{val} "
			return true if val == v
			
			@visit[val] = true
			return self._check_cycle( val, v )
		end
		return false
	end

end

g = Graph.new
g.add(:A,:B)
g.add(:A,:E)
g.add(:B,:C)
g.add(:C,:F)
g.add(:C,:D)
g.add(:D,:E)
g.add(:E,:D)
g.add(:D,:B)

# for directed use below for end nodes
#g.add(:F,false)

# this has to actually be an edge of course
u = :F
v = :C

if g.in_cycle(u,v)
	puts
	puts "\n{#{u},#{v}} found inside cyclic structure\n" 
else
	puts
	puts "\n{#{u},#{v}} is not inside cyclic structure\n"
end