For each of the following 3 cases, pass the start state as an
argument to each search algorithm and define a predicate
'is_goal(GoalState).' for the goal state.


Case 1:
-------

  Start state: [[],[1,2,3,4],[]]
  Goal state:  [[1,4],[2],[3]]

Case 2:
-------

  Start state: [[1,4],[],[2,3]]
  Goal state:  [[],[1,3],[2,4]]


Case 3:
-------

  Start state: [[1,2,3,4],[],[]]
  Goal state:  [[],[],[1,2,3,4]]