node graph chain detector thingy

pairs.rb

class EdgeEmitter
  include Enumerable
  attr_accessor :edges

  def initialize(filename)
    # you should load the file and save the edges
  end

  # implementation of Enumerable is bonus points
  def length
    # how do you know how many edges there are?
  end

  def each
    # yield each edge once
  end
end

class Graph
  attr_accessor :nodes

  def initialize
    # setup @nodes to prepare for filling in edges
  end

  def add_edge(a, b)
    # create OR find existing Node for a and b and establish correct relations between the nodes
  end

  def possible_chains
    # identify each chain of connected nodes by looping over all nodes and creating a collection of their family_trees
  end

  def to_s
    # filter out smaller chains that are part of a larger chain
    # uniqify and sort the resulting chains to match desired output
  end
end

class Node
  attr_accessor :children
  attr_accessor :name
  attr_accessor :memoized_tree

  def initialize(name)
    # prepare node name and children container
  end

  def add_child(node)
    # add node to children
  endp

  def family_tree
    # memoize the result of recursing into all children and appending their family_tree to this nodes family tree
    # if you don't memoize you will get a infinite loop
    # also note this should return a FLAT array
  end

  def to_s
    self.name # this will make printing the result easier
  end
end

edge_emitter = EdgeEmitter.new("pairs") # "pairs" is a file in the current working directory
graph = Graph.new

edge_emitter.each { |a, b| # or edge_emitter.edges.each {} if you can't get Enumerable mixin to work
  graph.add_edge(a, b)
}

puts graph