path-distance 1

path-distance.rb

  def distance_between v,w
    dist = 0
    adj[v].each do |e| 
      dist =  e.weight if e.to == w
    end
    return dist
  end

  #receive a path str like "A-B-C", return length of that path
  def path_distance str
    pair, dist_sum, no_path = [], 0, false
    str.split('-').reduce do |from, to|
      pair << [from,to]
      to
    end
    for v,w in pair
      dist = distance_between(v,w)
      if dist == 0 
        no_path = true
        break
      else
        dist_sum += dist
      end
    end
    no_path ? "NO SUCH ROUTE" : dist_sum
  end