This is the kind of things that are a real pleasure to model in Haskell. Here is a nice solution: solve funcs = filter (matches funcs) (possibilities funcs

This is the kind of things that are a real pleasure to model in Haskell. Here is a nice solution: solve funcs = filter (matches funcs) (possibilities funcs) matches funcs truths = truths == zipWith (($).($truths).flip) funcs [0..] possibilities [] = [[]] possibilities (x:xs) = concatMap (\x -> [True:x, False:x]) (possibilities xs) all_of = ((and.).) one_of = ((or.).) none_of = (((not.or).).) the_above = take the_below = drop.(+1) main = mapM_ putStrLn $ zipWith (\i s -> "Answer number " ++ (show i) ++ " is " ++ (show s)) [1..] $ head $ solve [ all_of the_below, none_of the_below, all_of the_above, one_of the_above, none_of the_above, none_of the_above ]