day 2 haskell

hs/02.1.hs

@@ -0,0 +1,24 @@
+import System.IO
+
+main = do
+    file <- readFile "../input/02"
+    let (x, y) = foldl step (0, 0) $ map parse $ lines file
+    print (x, y, x * y)
+
+parse s =
+    case name of
+        "up" -> Up n
+        "down" -> Down n
+        "forward" -> Forward n
+    where
+        [name, x] = words s
+        n = read $ x
+    
+parse :: String -> Action
+
+data Action = Up Int | Down Int | Forward Int
+
+step (x, y) (Up n) = (x, y - n)
+step (x, y) (Down n) = (x, y + n)
+step (x, y) (Forward n) = (x + n, y)
+step :: (Int, Int) -> Action -> (Int, Int)

hs/02.2.hs

@@ -0,0 +1,24 @@
+import System.IO
+
+main = do
+    file <- readFile "../input/02"
+    let (a, x, y) = foldl step (0, 0, 0) $ map parse $ lines file
+    print (x, y, x * y)
+
+parse s =
+    case name of
+        "up" -> Up n
+        "down" -> Down n
+        "forward" -> Forward n
+    where
+        [name, x] = words s
+        n = read $ x
+    
+parse :: String -> Action
+
+data Action = Up Int | Down Int | Forward Int
+
+step (a, x, y) (Up n) = (a - n, x, y)
+step (a, x, y) (Down n) = (a + n, x, y)
+step (a, x, y) (Forward n) = (a, x + n, y + a * n)
+step :: (Int, Int, Int) -> Action -> (Int, Int, Int)