Added alternate solution to Day 2-2 that doesn't use applicative.

2_alt.hs

@@ -0,0 +1,28 @@
+import Data.List
+
+checksum :: [[Int]] -> Int
+checksum = sum . map (\line -> maximum line - minimum line)
+
+divsum :: [[Int]] -> Int
+divsum = sum . map divline
+
+divline :: [Int] -> Int
+divline ns =
+    let (n, m) = catTupleMaybes $ map (\x -> (x, find (greaterAndDivisible x) ns)) ns
+    in  n `div` m
+    where
+        greaterAndDivisible :: Int -> Int -> Bool
+        greaterAndDivisible n m = n > m && n `mod` m == 0
+
+catTupleMaybes :: [(Int, Maybe Int)] -> (Int, Int)
+catTupleMaybes [] = (0, 1)
+catTupleMaybes ((t1, mt2):ts) = case mt2 of
+    Just t2 -> (t1, t2)
+    Nothing -> catTupleMaybes ts
+
+main :: IO ()
+main = do
+    input <- readFile "2.txt"
+    let grid = map (map read . words) $ lines input :: [[Int]]
+    print $ checksum grid
+    print $ divsum   grid