There are 2 robots in the problem. Robot #1 goes from: init1 -> 1 -> 2 -> 3. Robot #2 goes from: init2 -> 4 -> 2 -> 5. The states are encoded as: init# / s#a#a# For init#, # means the robot number. For s#a#a#, The first one is the # of robots. The second one is the cell #. The third one is the number of times that the robot has visited this cell. For example, s1a4a2 means the Robot #1 is in cell #4 for the 2nd time.