Add Day 3, Puzzle 1 solution

src/Day03.hs

@@ -0,0 +1,25 @@
+module Day03
+  ( day03_1,
+  )
+where
+
+getBankJoltage :: String -> Int
+getBankJoltage bank = read [x, y]
+    where x = maximum $ init bank
+          y = maximum bank'
+          bank' = drop 1 $ dropWhile (/= x) bank
+
+getTotalJoltage :: [String] -> Int
+getTotalJoltage banks = sum $ map getBankJoltage banks
+
+parseInput :: IO [String]
+parseInput = do
+  lines <$> readFile "input/day3.txt"
+
+day03_1 :: IO ()
+day03_1 = do
+  banks <- parseInput
+  let joltage = getTotalJoltage banks
+  putStrLn $
+    "Day 3, Puzzle 1 solution: "
+      ++ show joltage