The following figure shows a "Grid World problem, in which (1) the grey and solid block represents a barrier; (2) the robot can get the reward of +1 and -1 when it goes to the position of (4,3) or (4,2), while the rewards for any other positions are 0. Question: Use the discounted reward with the discount factor of 0.9 to compute Q values in this problem and determine the best actions at each position ( don't need to consider Q values and actions at (4, 3) and (4 , 2) ). 3 | 11 - 1 1 1 2 3 4