Answer of FASHION at SPOJ

gistfile1.hs

import Data.List
import Data.Int
import Data.Char

type Z = Int

myMapReadWords :: String -> [Z]
myMapReadWords ('1':'0':' ':rest) = 10 : myMapReadWords rest
myMapReadWords ('1':'0':[]) = 10 : []
myMapReadWords (a:' ':rest) = digitToInt a : myMapReadWords rest
myMapReadWords (a:[]) = digitToInt a : []

solve input = 
  unlines $ solveProblems problems
  where
    ls = lines input
    n  = (read $ head ls)::Z
    getProblems [] = []
    getProblems (n:ms:ws:rest) = 
      (myMapReadWords ms, myMapReadWords ws) : getProblems rest
    problems = (getProblems $ tail ls) :: [([Z], [Z])]
    solveProblem (ms,ws) = 
      sum $ map (\(a,b)->a*b) $ zip (sort ms) (sort ws)
    solveProblems = map (show.solveProblem)

main = interact solve

myMapReadWords = map read $ words , much faster implementation