Add Day 3, Puzzle 2 solution

- Implement generalized function for Puzzle 2
    - Use generalized function also for Puzzle 1

src/Day03.hs

@@ -1,16 +1,19 @@
 module Day03
   ( day03_1,
+    day03_2
   )
 where
 
-getBankJoltage :: String -> Int
-getBankJoltage bank = read [x, y]
-    where x = maximum $ init bank
-          y = maximum bank'
-          bank' = drop 1 $ dropWhile (/= x) bank
+getBankJoltage :: String -> Int -> String -> Int 
+getBankJoltage value 0 _ = read value
+getBankJoltage value n bank =
+  let l = length bank
+      bank' = take (l - n + 1) bank
+      x = maximum bank'
+   in getBankJoltage (value ++ [x]) (n - 1) (drop 1 (dropWhile (/= x) bank)) 
 
-getTotalJoltage :: [String] -> Int
-getTotalJoltage banks = sum $ map getBankJoltage banks
+getTotalJoltage :: [String] -> Int -> Int
+getTotalJoltage banks n = sum $ map (getBankJoltage "" n) banks
 
 parseInput :: IO [String]
 parseInput = do
@@ -19,7 +22,15 @@ parseInput = do
 day03_1 :: IO ()
 day03_1 = do
   banks <- parseInput
-  let joltage = getTotalJoltage banks
+  let joltage = getTotalJoltage banks 2
   putStrLn $
     "Day 3, Puzzle 1 solution: "
       ++ show joltage
+
+day03_2 :: IO ()
+day03_2 = do
+  banks <- parseInput
+  let joltage = getTotalJoltage banks 12
+  putStrLn $
+    "Day 3, Puzzle 2 solution: "
+      ++ show joltage

src/Main.hs

@@ -2,7 +2,7 @@ module Main (main) where
 
 import Day01 (day01_1, day01_2)
 import Day02 (day02_1, day02_2)
-import Day03 (day03_1)
+import Day03 (day03_1, day03_2)
 import System.Environment (getArgs)
 
 main :: IO ()
@@ -20,12 +20,15 @@ main = do
       day02_1
       day02_2
     "3" : "1" : _ -> day03_1
+    "3" : "2" : _ -> day03_2
     "3" : _ -> do
       day03_1
+      day03_2
     "all" : _ -> do
       day01_1
       day01_2
       day02_1
       day02_2
       day03_1
+      day03_2
     _ -> error "Not implemented"