You can put this solution on YOUR website! You'll have to explain the problem, because very few of us will know that the Kaliningrad Circus problem is, and almost none will have your textbook. Google lists a "Kaliningrad problem" that pertains more to economics and has nothing to do with circuses. Also, Kaliningrad was formerly named Königsberg, and there is a famous problem in graph theory called the Königsberg bridge problem, in which you had to cross the bridges of Königsberg without going over the same bridge twice.
