Five friends gather for a marathon bridge session. They want to play ten rubbers, such that each person has each possible partner for two rubbers and sits out two rubbers. Moreover, the two times any given partners play together must NOT both involve the same pair of opponents.
I spent much of this morning convinced that these criteria were impossible to meet (but not sure how to prove it). But then I realized exactly how to do it and felt stupid.
(Hint: The more instinctively you know the best way to set up a five-person round robin, the more you're at risk of falling into a mental trap.)
Posted by Matt Bruce at July 31, 2007 12:17 PM