Question -
On a 2-D regular (not wrapped-around) mesh, a message from a source (Xs, Ys) is to be sent to a destination (Xd, Yd). If any shortest path can be used, what is the probability that the message follows the shortest path which would be selected by the X-Y routing algorithm? Derive the probability in terms of Xs, Xd, Ys and Yd.