\(a,b,c) d -> case d of
1 -> let a' = a + 1 in a' `seq` (a',b,c)
2 -> let b' = b + 1 in b' `seq` (a,b',c)
3 -> let c' = c + 1 in c' `seq` (a,b,c')
_ -> (a,b,c)
) (0,0,0)
unfoldr (\case
(a:r@(b:_)) -> Just (b - a, r)
[_] -> Just (3,[])
_ -> Nothing
) . (0:) . sort
snd $ IM.findMax m where
l = foldr (\a r -> case r of
[] -> [a, a + 3]
_ -> a:r
) [] $ sort l'
m = IM.insert 0 1 $ IM.fromList $ fmap (\k ->
(k, sum $ mapMaybe (\d ->
IM.lookup (k - d) m
) [1 .. 3])
) l
main = do
[fn] <- getArgs
jrs <- (map read . words) <$> readFile fn
let
(s,_,t) = distribution $ differences jrs
print $ fromIntegral s * fromIntegral t
print $ arrangements jrs
foldl' (