temp

app/12.hs

@@ -7,34 +7,44 @@ import Data.List
 import Debug.Trace
 import Data.Maybe
 
+type Pos = (Int,Int)
+
 parse :: String -> Matrix Char
 parse = fromLists . lines
 
-getGroup :: (Int,Int) -> Matrix Char -> [(Int,Int)]
+getGroup :: Pos -> Matrix Char -> [Pos]
 getGroup (i,j) s =
   let e = getElem i j s in
     go e [(i,j)] []
-    where go :: Char -> [(Int,Int)] -> [(Int,Int)] -> [(Int,Int)]
+    where go :: Char -> [Pos] -> [Pos] -> [Pos]
           go _ [] v = v
           go c (x@(i,j):xs) v
             | x `elem` v = go c xs v
             | uncurry safeGet x s /= Just c = go c xs v
             | otherwise = go c (filter (isJust . flip (uncurry safeGet) s) [(i+1,j),(i-1,j),(i,j+1),(i,j-1)] ++ xs) (x:v)
 
-groups :: Matrix Char -> [[(Int,Int)]]
+groups :: Matrix Char -> [[Pos]]
 groups s = go [(i,j) | i <- [1 .. nrows s], j <- [1 .. ncols s]] []
-  where go :: [(Int,Int)] -> [[(Int,Int)]] -> [[(Int,Int)]]
+  where go :: [Pos] -> [[Pos]] -> [[Pos]]
         go [] v = v
         go (x:xs) v
           | any (x `elem`) v = go xs v
           | otherwise = go xs (nub (getGroup x s):v)
 
-perimeter :: [(Int,Int)] -> Int
+perimeter :: [Pos] -> Int
 perimeter s = length $ s >>= \(i,j) -> [(i,j+1),(i,j-1),(i+1,j),(i-1,j)] \\ s
 
 solve1 :: Matrix Char -> Int
 solve1 s = let g = groups s; p = perimeter <$> g in sum $ zipWith (*) (length <$> g) p
 
+sides :: [Pos] -> Int
+sides s = length $ go s []
+  where go :: [Pos] -> [(Pos,Pos)] -> [(Pos,Pos)]
+        go [] v = v
+        go ((y,x):xs) v
+          | any (\((y1,x1),(y2,x2)) -> (x == x1 && y1 <= y && y <= y2) || (y == y1 && x1 <= x && x <= x2)) v = go xs v
+          | otherwise = undefined
+
 solve2 :: Matrix Char -> Int
 solve2 = undefined