God this is cluttered

app/2.hs

@@ -0,0 +1,30 @@
+{-# LANGUAGE LambdaCase, MultiWayIf #-}
+module Main where
+
+import Data.Functor
+
+parse :: String -> [[Int]]
+parse = ((read <$>) . words <$>) . lines
+
+solve1 :: [[Int]] -> Int
+solve1 =
+  let di a = all (\a' -> a' <  4 && not (a' <= 0)) a ||
+             all (\a' -> a' > -4 && not (a' >= 0)) a in
+  sum . ((\a -> if di $ zipWith (flip (-)) a (tail a) then 1 else 0) <$>)
+
+solve2 :: [[Int]] -> Int
+solve2 =
+  let r [] = [[]]
+      r (r':rs) = rs:((r':) <$> r rs)
+      di a = all (\a' -> a' <  4 && not (a' <= 0)) a ||
+             all (\a' -> a' > -4 && not (a' >= 0)) a in
+  sum . ((\a ->
+            if any (\b -> di $ zipWith (flip (-)) b (tail b)) a
+            then 1 else 0) .
+         r <$>)
+
+
+main :: IO ()
+main = readFile "inputs/2" <&> parse >>= \i ->
+       print (solve1 i) >>
+       print (solve2 i)