finished day 14 part 2

1 files changed, 14 insertions, 1 deletions

diff --git a/Puzzle14.hs b/Puzzle14.hs
index d536c8d..c904d4a 100644
--- a/Puzzle14.hs
+++ b/Puzzle14.hs
@@ -1,6 +1,7 @@
 import Puzzle10 (knotHash)
 import qualified Data.Map as Map
 import Data.Map (Map)
+import Data.Maybe (catMaybes)
 -- import Data.Char (digit2Int)
 
 hex2Bin '0' = "0000"
@@ -41,4 +42,16 @@ mat2Map xs = Map.fromList $ mconcat $ fmap f $ zipWith (,) [0 .. length xs - 1]
 step :: (Int, [(Int, Int)], Map (Int, Int) Bool) -> Int
 step (n, queue, mat)
   | null mat = n
-  | null queue = head $ Map.toList mat
+  | null queue = let (z, b) = head $ Map.toList mat in
+                   if b then step (n + 1, [z], Map.delete z mat) 
+                        else step (n, [], Map.delete z mat)
+  | otherwise = step (n, catMaybes (zipWith f nbhd $ flip Map.lookup mat <$> nbhd) ++ zs, Map.delete (x, y) mat)
+                   where (x, y):zs = queue
+                         nbhd = [(x + 1, y), (x - 1, y), (x, y + 1), (x, y - 1)]
+
+f :: (Int, Int) -> Maybe Bool -> Maybe (Int, Int)
+f x (Just True) = Just x
+f x _ = Nothing
+
+solve2 :: [Char] -> Int
+solve2 xs = step (0, [], mat2Map $ truthMat xs)