Refactor code

src/Day01.hs

@@ -0,0 +1,34 @@
+{-# OPTIONS_GHC -Wno-incomplete-uni-patterns #-}
+
+module Day01
+  ( day01_1,
+    day01_2,
+  )
+where
+
+import Data.List (group, sort, transpose, uncons)
+import Data.Maybe (fromJust)
+
+listDistance :: [Int] -> [Int] -> Int
+listDistance xs ys = sum $ map abs $ zipWith (-) (sort xs) (sort ys)
+
+similarityScore :: [Int] -> [Int] -> Int
+similarityScore xs ys =
+  let elemsY = [(fst . fromJust $ uncons y, length y) | y <- (group . sort) ys]
+   in sum [x * snd y | x <- xs, y <- elemsY, x == fst y]
+
+day01_1 :: IO ()
+day01_1 = do
+  contents <- lines <$> readFile "input/day1.txt"
+  let [x, y] = transpose $ map read . words <$> contents
+  putStrLn $
+    "Day 1, Puzzle 1 solution: "
+      ++ show (listDistance x y)
+
+day01_2 :: IO ()
+day01_2 = do
+  contents <- lines <$> readFile "input/day1.txt"
+  let [x, y] = transpose $ map read . words <$> contents
+  putStrLn $
+    "Day 1, Puzzle 2 solution: "
+      ++ show (similarityScore x y)