Add day 1 in Haskell

2019/1/day1.hs

@@ -0,0 +1,17 @@
+import System.IO  
+import Text.Printf
+
+main :: IO ()
+main = do
+  content <- getContents
+  let input = map read (lines content)
+  printf "Part 1: %d\n" (fuel input)
+  printf "Part 2: %d\n" (fuelrec input)
+
+fuel :: [Int] -> Int
+fuel xs = sum (map (subtract 2 . (`div` 3)) xs)
+
+fuelrec :: [Int] -> Int
+fuelrec xs = sum (map f xs) - sum xs where
+    f x | x > 0 = x + f ((subtract 2 . (`div` 3)) x)
+        | otherwise = 0