Solve day 2, part 1

src/Day2.hs

@@ -4,12 +4,10 @@ module Day2 (day2) where
 
 import qualified Data.Text as T
 import qualified Data.Attoparsec.Text as P
-import Data.List (elemIndices)
 
-type Max = Int
-type Min = Int
+type Max = Integer
+type Min = Integer
 type Letter = Char
-type Validator = Policy -> String -> Bool
 
 data Policy = Policy { lBound :: Min
                      , uBound :: Max
@@ -26,34 +24,20 @@ parserPolicy = do
     _ <- P.string ": "
     return $ Policy lB uB le
 
-validatePolicy :: Validator
+validatePolicy :: Policy -> String -> Bool
 validatePolicy p s =
-    let l = length $ filter (== letter p) s in
+    let l = toInteger . length $ filter (== letter p) s in
     l >= lBound p && l <= uBound p
 
-validateLine :: Validator -> String -> Bool
-validateLine v s =
+validateLine :: String -> Bool
+validateLine s =
     case P.parse parserPolicy (T.pack s) of
         P.Fail {} -> error "day2 - parser error"
         P.Partial _ -> error "day2 - input error"
-        P.Done i r -> v r (T.unpack i)
-
-xor :: Bool -> Bool -> Bool
-xor True = not
-xor False = id
-
-validateCorrectPolicy :: Validator
-validateCorrectPolicy p s =
-    let index1 = lBound p - 1
-        index2 = uBound p - 1
-        indices = elemIndices (letter p) s in
-        xor (index1 `elem` indices) (index2 `elem` indices)
-
+        P.Done i r -> validatePolicy r (T.unpack i)
 
 day2 :: IO ()
 day2 = do
-  rs <- lines <$> readFile "./input/day2"
-  putStr "[Day 2-1] # valid passwords: "
-  print . length . filter (==True) . fmap (validateLine validatePolicy) $ rs
-  putStr "[Day 2-2] # valid passwords: "
-  print . length . filter (==True) . fmap (validateLine validateCorrectPolicy) $ rs
+  r <- readFile "./input/day2"
+  putStr "[Day 1-1] # valid passwords: "
+  print . length . filter (==True) . fmap validateLine . lines $ r