Day 18: Some Progress

goal needs to be x, so moved into the list comprehension

2019/day18/day18.hs

@@ -4,22 +4,35 @@ module Main where
 import Data.List
 import Data.List.Split
 import Data.List.Utils
+import Data.Char
 import qualified Data.Map.Strict as M
+import qualified Data.Set as S
 import Data.Maybe
 import Helpers
 import Linear.V2
+import Debug.Trace
 
 type DungeonMap = M.Map (V2 Int) Char
+data Distance = Reachable Int | Unreachable deriving (Show, Eq)
+
+instance Num Distance where
+    Reachable x + Reachable y = Reachable (x+y)
+    Unreachable + _ = Unreachable
+    _ + Unreachable = Unreachable
+
+instance Ord Distance where
+    Reachable x <= Reachable y = x<=y
+    Unreachable <= _ = False
+    _ <= Unreachable = True
 
 main :: IO ()
 main = do
-  map <- updateScreenBuffer M.empty (0, 0) <$> readFile "testinput1"
+  dMap <- updateScreenBuffer M.empty (0, 0) <$> readFile "testinput1"
-  putStrLn $ drawMap map
+  putStrLn $ drawMap dMap
-  let spos = findPos '@' map
+  print $ distanceFromTo dMap '@' 'f'
-  let epos = findPos 'e' map
+  print $ distanceFromTo dMap '@' 'a'
-  print $ getNeighbors map spos
+  print $ distanceFromTo dMap '@' 'A'
-  print $ getNeighborsMap map (getNeighbors map spos)
+  print $ tls1 dMap (S.fromList "abcdef") 'f'
-  print $ distanceFromTo map '@' 'd'
 
 updateScreenBuffer :: DungeonMap -> (Int, Int) -> String -> DungeonMap
 updateScreenBuffer buf _ [] = buf
@@ -39,24 +52,43 @@ getNeighbors m coord =
   M.fromList
     [ (u + coord, M.findWithDefault '#' (u + coord) m)
     | u <- unitVecs
-    , M.findWithDefault '#' (u + coord) m /= '#'
+    , let c = M.findWithDefault '#' (u + coord) m  in c `elem` ".@⌂" || isLower c
     ]
 
 getNeighborsMap :: DungeonMap -> DungeonMap -> DungeonMap
 getNeighborsMap m n = M.unions [getNeighbors m x | (x, _) <- M.toList n]
 
-distanceFromTo :: DungeonMap -> Char -> Char -> Int
+distanceFromTo :: DungeonMap -> Char -> Char -> Distance
-distanceFromTo dmap schar echar =
+distanceFromTo dMap schar echar =
-  distanceFromTo' dmap (M.singleton spos schar) spos epos 1
+  distanceFromTo' dMap (M.singleton spos schar) spos epos 1
   where
-    spos = findPos schar dmap
+    spos = findPos schar dMap
-    epos = findPos echar dmap
+    epos = findPos echar dMap
-    distanceFromTo' mMap nMap start end n =
+    distanceFromTo' mMap nMap start end n
-      if M.member end newNMap
+      | M.member end newNMap = Reachable n
-        then n
+      | newNMap == nMap = Unreachable
-        else distanceFromTo' mMap newNMap start end (n + 1)
+      | otherwise = distanceFromTo' mMap newNMap start end (n + 1)
       where
         newNMap = M.union nMap (getNeighborsMap mMap nMap)
+        --todo: maek tail recursive
 
 findPos :: Char -> DungeonMap -> V2 Int
 findPos c = head . M.keys . M.filter (`elem` [c])
+
+-- tracePath :: DungeonMap -> Char -> String -> Maybe Int
+-- tracePath dMap _ [] = Just 0
+-- tracePath dMap c (x:xs) = case distanceFromTo dMap c x of
+--                             Nothing -> Nothing
+--                             Just y -> let trace = tracePath dMap c xs in if isJust trace then Just (y + fromJust trace) else Nothing
+tls1 :: DungeonMap -> S.Set Char -> Char -> Distance
+tls1 dMap nodeSet goal
+  | S.size nodeSet == 1 = (distanceFromTo dMap '@' (head $ S.toList nodeSet))
+  -- ^ S = {c}, different 1 element sets possible?
+  | otherwise =
+    minimum
+      [tls1 dMap sMinusC x + distanceFromTo newDMap x goal | x <- S.toList sMinusC]
+  where
+    sMinusC = traceShowId (S.delete goal nodeSet)
+    newDMap = traceShowId (M.insert door '⌂' dMap)
+    door = traceShowId (findPos (toUpper (traceShowId goal)) dMap)
+-- tls2 = undefined