Bowling

dp82Difficult.hs

import Control.Applicative
import Control.Arrow

game = scanl1 (+) . getFrameScores . getFrames
    where 
        getFrames xs = 	if length scores == 10 then scores 
                        else (take 9 scores) ++ [concat $ drop 9 scores]
                            where 
                                scores = parseScores xs
                                         parseScores [] = []
                                         parseScores xs = case head xs of
                                                          10 -> [10] : (parseScores $ tail xs)
                                                          _  -> (take 2 xs) : (parseScores $ drop 2 xs)
        getFrameScores (x:[]) = [sum x]
        getFrameScores (x:xs) = case length x of
                                1 ->  case length next of 
                                      1 -> sum (head <$> [x, next, nnext]) : getFrameScores xs
                                      _ -> head x + (sum $ take 2 next) : getFrameScores xs
                                           where (next, nnext) = head &&& last $ take 2 xs
                                2 ->  case sum x of
                                      10 -> sum x + next : getFrameScores xs
                                      _  -> sum x : getFrameScores xs
                                          where next = head $ head xs
                                _ ->  error "Parse error on frame. More than two turns."