The ACCB problem is a real-world scheduling problem for the 1998 ACC Basketball league.
Solution
The direct approach of enumerating the constraints does not lead to an efficient solution. Instead, the problem is broken into 3 subproblems which can each be solved efficiently.
Social Golfer Problem (CSPLib 10)
This problem also appeared in the real world when a golf course manager wanted to make an as long as possible schedule for a group of 32 players in his club.
Solution
The problem became a bechmark because of its uncommon number of symmetries. A solution for 32 players, 8 groups and W weeks leads to
32! * W! * [(8 * W) ^ 8!]
symmetric solutions. Therefore prunning the search space by reducing symmetry is essential for an efficient solution.
An Introduction (K. Marriot, P.Stuckey)