Google Code Jam/Text Messaging Outrage

Solution

main = (enumFromTo (1::Int) <$> readLn) >>= mapM_ go
  where go i = do
          [p,k,l] <- map read . words <$> getLine
          nn <- map read . words <$> getLine
          printf "Case #%i: %i\n" i (solve k nn)

solve :: Int -> [Integer] -> Integer
solve k l = let rounds = map sum $ chunks k $ sortBy (flip compare) l
              in sum $ zipWith (*) [1..] rounds
chunks n [] = []
chunks n as = bs : chunks n cs where (bs,cs) = splitAt n as