Implement day 1+2

.gitignore

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+*.hi
+*.o

1.hs

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+{-# LANGUAGE ScopedTypeVariables #-}
+
+main = do
+    lines <- readFile "1.in"
+    putStrLn . show . solve . map (read :: String -> Integer) . words $ lines
+    where
+        solve = partB
+
+-- solves all lines, returns a string
+-- solve :: [string] -> a
+partA = sum . map (boolToInt . cmpTuple) . double
+    where 
+        double = zip <*> tail
+        cmpTuple = uncurry (<)
+        boolToInt = fromEnum
+
+partB = partA . sumTuple3 . triple
+    where 
+        triple x = zip3 x (tail x) (tail $ tail x)
+        sumTuple3 = map (\(x, y, z) -> x + y + z) 

2.hs

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+{-# LANGUAGE ScopedTypeVariables #-}
+
+main = do
+    lines <- readFile "2.in"
+    putStrLn . show . solve . parseInput . words $ lines
+    where
+        solve = partB
+        parseInput :: [ String ] -> [ (String, Integer) ]
+        parseInput [] = []
+        parseInput [x] = []
+        parseInput (x:y:r) = (x, read y) : parseInput r
+
+-- solves all lines, returns a string
+partA :: [(String, Integer)] -> Integer
+partA = (uncurry (*)) . foldl parseCommand (0,0)
+    where
+        -- (horizontal, vertical)
+        parseCommand (a, b) ("forward", x) = (a + x, b)
+        parseCommand (a, b) ("down", x) = (a, b + x)
+        parseCommand (a, b) ("up", x) = (a, b - x)
+        parseCommand _ _ = (0, 0)
+
+partB :: [(String, Integer)] -> Integer
+partB = (\(x,y,_) -> x * y) . foldl parseCommand (0, 0, 0)
+    where
+        -- (horiz, vert, aim)
+        parseCommand (a, b, c) ("forward", x) = (a + x, b + c * x, c)
+        parseCommand (a, b, c) ("down", x) = (a, b, c + x)
+        parseCommand (a, b, c) ("up", x) = (a, b, c - x)
+        parseCommand _ _ = (0, 0, 0)

Makefile

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+target:
+	ghc 1.hs
+	ghc 2.hs