Google Code Jam 2016 Qualification Round : Problem A. Counting Sheep

a.hs

import Data.List
import Debug.Trace
import Control.Applicative

testloop :: Integer -> Integer -> IO String
testloop n t | n>t = return ""
testloop n t = getLine >>= teststr >>= \x->return ("Case #"++(show n)++": "++x) >>= putStrLn >> testloop (n+1) t

teststr :: String -> IO String
teststr s = disp $ dropWhile check0to9 $ concatnums $ numlist 1 s

numlist :: Integer -> String -> [String]
numlist n s | n < 1000 =
	--trace("Debug[1]: "++x) (x:xs)
	x:xs
	where
		x = show $ (*n) $ read s
		xs= numlist (n+1) s
numlist n s = []

concatnums :: [String] -> [[String]]
concatnums xs = scanl (\x y->x++y:[]) [] xs

check0to9 :: [String] -> Bool
check0to9 s = case sort $ nub $ concat s of
	-- "0123456789" -> trace("Debug[2]: "++(concat s)) (False)
	-- _ -> trace("Debug[2]: "++(concat s)) (True)
	"0123456789" -> False
	_ -> True

disp :: [[String]] -> IO String
disp (x:xs) = return $ last x
disp ([]) = return "INSOMNIA"

main = getLine >>= \x-> testloop 1 $ read x