counter.hs

module Counter
  (Element(..),
   countUnique,
   countUnique2) where


data Element = Element { s :: String,
                         e1 :: Int,
                         e2 :: Int } deriving (Show, Eq)



countUnique :: [Element] -> Int
countUnique [] = 0
countUnique (x:xs) | x `foundIn` xs = countUnique xs
                   | otherwise = 1 + countUnique xs
  where foundIn :: Element -> [Element] -> Bool
        foundIn x [] = False
        foundIn x xs = any (== 0) $ map (compare x) xs 
          where compare :: Element -> Element -> Int
                compare a b | (e2 a) == (e2 b) = 0
                            | (e1 a) /= (e1 b) = (e1 b) - (e1 a)
                            | otherwise = (e2 b) - (e2 a)


countUnique2 :: [Element] -> Int
countUnique2 [] = 0
countUnique2 (x:xs) = let foundIn :: Element -> [Element] -> Bool
                          foundIn x [] = False
                          foundIn x xs = any (== 0) $ map (compare x) xs
                            where compare :: Element -> Element -> Int
                                  compare a b | (e2 a) == (e2 b) = 0
                                              | (e1 a) /= (e1 b) = (e1 b) - (e1 a)
                                              | otherwise = (e2 b) - (e2 a)
                      in
                        case () of _
                                     | x `foundIn` xs -> countUnique2 xs
                                     | otherwise -> 1 + countUnique2 xs


countUnique3 :: [Element] -> Int
countUnique3 [] = 0
countUnique3 (x:xs) | foundIn xs = countUnique3 xs
                    | otherwise = 1 + countUnique3 xs
  where foundIn :: [Element] -> Bool
        foundIn [] = False
        foundIn xs = any (== 0) $ map (compare) xs 
          where compare :: Element -> Int
                compare b   | (e2 x) == (e2 b) = 0
                            | (e1 x) /= (e1 b) = (e1 b) - (e1 x)
                            | otherwise = (e2 b) - (e2 x)

countertest.hs

import Counter

main = do print $ countUnique [ Element "zak" 2 0,
                                Element "mac" 3 1,
                                Element "abc" 4 2,
                                Element "zak" 5 0 ]