solved day 3 part A

Main.hs

@@ -11,52 +11,23 @@ import Data.Attoparsec.Text
 
 main :: IO ()
 main = do
-    inputs <- TIO.readFile "input.txt"
-    let Just entries = maybeResult $ parse entriesParser inputs
-    TIO.putStrLn $ T.pack $ show $ sum $ entries2ints entries
-
-data Entry = Entry
-  { policy :: Policy
-  , password :: String
-  } deriving (Show,Read)
-
-data Policy = Policy
-  { first :: Int
-  , second :: Int
-  , character :: Char
-  } deriving (Show, Read)
-
-policyParser :: Parser Policy
-policyParser = do
-    frst <- many digit
-    string "-"
-    scnd <- many digit
-    space
-    character <- letter
-    let Right (first, _) = TR.decimal $ T.pack $ frst
-    let Right (second, _) =  TR.decimal $ T.pack $ scnd
-    return Policy { first = first - 1, second = second - 1, character = character }
-
-entryParser :: Parser Entry
-entryParser = do
-    policy <- policyParser
-    char ':'
-    space
-    password <- many letter
-    endOfLine
-    return Entry { policy = policy, password = password }
-
-checkEntry :: Entry -> Bool
-checkEntry e = let p = policy e
-                   frst = first p
-                   scnd = second p
-                   indicies = findIndices ((character p)==) (password e)
-               in ((frst `elem` indicies) && (scnd `notElem` indicies)) || ((frst `notElem` indicies) && (scnd `elem` indicies))
-
-entriesParser :: Parser [Entry]
-entriesParser = do
-    entries <- many entryParser
-    return entries
-
-entries2ints :: [Entry] -> [Int]
-entries2ints es = map (\e -> if checkEntry e then 1 else 0) es
+    input <- TIO.readFile "input.txt"
+    let slope = treeMap $ map T.unpack $ T.lines input
+    let hits = map (hitTree slope) $ tobogganLocations 1 3 (length slope) (length $ head slope)
+    let answer = sum $ map (\x -> if x then 1 else 0) hits
+    TIO.putStrLn $ T.pack $ show answer
+
+treeMap :: [String] -> [[Bool]]
+treeMap tts = map (map ('#' ==)) tts
+
+tobogganLocations :: Int -> Int -> Int -> Int -> [(Int, Int)]
+tobogganLocations x y h w = if x == h
+                            then []
+                            else (x, y): let y' = (y + 3) `mod` w
+                                             x' = x + 1
+                                         in tobogganLocations x' y' h w
+
+hitTree :: [[Bool]] -> (Int, Int) -> Bool
+hitTree bbs (x, y) = (bbs !! x) !! y
+
+