{-# LANGUAGE FlexibleContexts, OverloadedStrings #-} import Control.Applicative import Control.Monad import qualified Data.ByteString.Char8 as B import Data.Maybe (fromJust) import Text.Printf import Debug.Trace import Data.Array.IArray getInts :: IO [Int] getInts = map (fst . fromJust . B.readInt) . B.words <$> B.getLine imap :: (IArray a e, Ix i, Enum i) => (i,i) -> (i -> i) -> a i e -> e -> a i e imap (a,b) f arr e = listArray (a,b) (repeat e) // [(i', arr!i) | i <- [a..b], let i' = f i, a <= i', i' <= b] f [] tot memo = memo!tot f (x:xs) tot memo = f xs tot memo' where memo_plus = amap (\e -> e ++ "+") $ imap (0, tot) (\i -> i+x) memo "%" memo_prod = amap (\e -> e ++ "*") $ imap (0, tot) (\i -> i*x) memo "%" memo' = array (0,tot) $ zipWith (\(i1,x1) (_,x2) -> (i1, max x1 x2)) (assocs memo_plus) (assocs memo_prod) main = do [n] <- getInts [tot] <- getInts xs <- getInts let memo = listArray (0,tot) (repeat "%") :: Array Int String putStrLn $ f (tail xs) tot (memo // [(head xs, "")])