day 12 part 1

2022/day12.hs

@@ -0,0 +1,54 @@
+import qualified Data.Array as A
+import qualified Data.Map as M
+import Data.Char (ord)
+import Data.List (findIndex, find)
+import Data.Maybe (isJust, mapMaybe, listToMaybe, fromJust)
+
+type Height = Int -- bool identifies if this is our final square
+type Coord = (Int, Int)
+type HeightMap = A.Array Coord Height
+
+
+bfs :: HeightMap -> [(Coord, Int)] -> M.Map Coord Int -> M.Map Coord Int
+bfs heightmap [] visited = visited
+bfs heightmap ((q@(x,y), dist):queue) visited = if usable
+        then bfs heightmap queue' visited'
+        else bfs heightmap queue visited
+        where
+            current = heightmap A.! q
+            inRange (x,y) = let (bx, by) = snd (A.bounds heightmap) in x >= 0 && x <= bx && y >= 0 && y <= by
+            reachable coord = inRange coord && (heightmap A.! coord) <= current + 1
+            neighs = filter reachable [(x+1, y), (x-1, y), (x, y+1), (x, y-1)]
+            usable = case M.lookup q visited of
+                                                Nothing -> True
+                                                (Just d) -> d > dist
+            visited' = M.insert q dist visited
+            queue' = queue ++ map (,dist+1) neighs
+
+toHeight :: Char -> Int
+toHeight 'S' = toHeight 'a'
+toHeight 'E' = toHeight 'z'
+toHeight x = ord x
+
+findIndex2 :: (a -> Bool) -> [[a]] -> Maybe (Int, Int)
+findIndex2 f xss = listToMaybe xs2 where
+    xs = zip [0..] $ map (findIndex f) xss
+    xs2 = mapMaybe (uncurry augment) xs
+    augment a (Just b) = Just (a,b)
+    augment a Nothing = Nothing
+    
+main = do
+    m <- lines <$> getContents
+
+    let start = fromJust  $ findIndex2 (=='S') m
+    let target = fromJust $ findIndex2 (=='E') m
+
+    let heightmap = A.listArray ((0,0), (length m - 1, length (head m) - 1)) (concatMap (map toHeight) m)
+    print heightmap
+
+    let final = bfs heightmap [(start, 0)] M.empty
+
+    print $ final M.! target
+
+
+    pure ()

2022/inputs/day12

@@ -0,0 +1,41 @@
+abccccccccccccccccaaccccccccccccccccccccaaaaaaaaaaaaacccccccccccccccccccccccccccccccccccccccccccccccccccccccaaaaaa
+abcccccccccccccaaaaaccccccccccccccccccccaaaaaaaaaaaaaccccccccccccccccccccccccccccccccccccccccccccccccccccccccaaaaa
+abccccccccccccccaaaaaccccccccccccccaaaaacccaaaaaacccccaaccccccccccccccccccccccccccccccccccccccccccccccccccccccaaaa
+abccccccccccccccaaaaacccccccccaacccaaaaacccaaaaaaaccccaaaacaacaaccccccccccccccccccccccccaaaccccaaaccccccccccccaaaa
+abcccccccccccccaaaaacccccccaaaaaccaaaaaacccaaaaaaaacaaaaaacaaaaaccccccccccccccccccccccccaaacccaaaaccccccccccccaaac
+abccccccaacaaaccccaaccccccccaaaaacaaaaaaccaaaacaaaacaaaaaccaaaaaaccccccccccccccccccccccccaaaaaaaacccccccccccccaacc
+abccccccaaaaaaccccccccccccccaaaaacaaaaaaccaaaaccaaaacaaaaacaaaaaacccccccccccccccccccccccaaaaaaaaaccccccccccccccccc
+abccccccaaaaaacccccccccccccaaaaaccccaaccccaacccccaaccaacaacaaaaaccccccccccccccccccccccccccaaakkkkllllcccaaaccccccc
+abccccccaaaaaaacccccccccccccccaaccccaacccccccccccccccccccccccaaaccccccaaaacccccccccjjjjkkkkkkkkkkllllccccaacaccccc
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+abcccccaaaaaaaaccaaaacccccccccccccccaaaaaccccccccccccccccaacaaccccccccaaaacccccccjjjjjjjkkkkkppppppplllccaaaaacccc
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+abccccccaacccccccaaaaacccccaaaccaaaaaaaaaaccaaaaaaccccccaaaaaaaaaacaaaccccccccccjjjoooouuuoopuuuuupppllcccaaaccccc
+abacccccaaccccccccccaacccccaaaaaaaccaaaaaaccaaaaaaccccccaaaaaccaaaaaaaccccaaccccjjoootuuuuuuuuuuuuvpqlllcccccccccc
+abaccaaaaaaaacccccccccccccccaaaaaaccaacccccccaaaaacccccccacaaaccaaaaaaccaaaacaccjjooottuuuuuuuxyuvvqqljjccddcccccc
+abcccaaaaaaaaccccccccccccaaaaaaaaacaacaaccccaaaaaccccccccccaaaaaaaaaacccaaaaaacciijootttxxxuuxyyyvvqqjjjjdddcccccc
+abcccccaaaaccccaaacccccccaaaaaaaaacaaaaaccccaaaaaccccccccccccaaaaaaaaacccaaaaccciiinntttxxxxxxyyvvqqqqjjjddddccccc
+abccccaaaaaccccaaaaacccccaaaaaaaaaaaaaaaaccccccccccccccccccccaaaaaaaaaaccaaaaccciiinntttxxxxxxyyvvvqqqqjjjdddccccc
+abccccaaaaaaccaaaaaccccccccaaaaaaaaaaaaaacccccccccccccccccccccccaaacaaacaacaaccciiinnnttxxxxxyyyvvvvqqqqjjjdddcccc
+SbccccaaccaaccaaaaacccccccccaaaaaaaaaaaaacccccccccccccccccccccccaaacccccccccccciiinnntttxxxEzzyyyyvvvqqqjjjdddcccc
+abcccccccccccccaaaaacccccccaaaaaaaaacaaaccccccccccccccccccccccccaaccccccccccccciiinnnttxxxxyyyyyyyyvvvqqqjjjdddccc
+abcccccccccccccaaccccccccccaaaaaaaaccccccccccccccccccccccccccccccccccccccccccciiinnntttxxyyyyyyyyyvvvvqqqjjjdddccc
+abccccccccccccccccccccccccaaaaaaaacccccccccccccccccccccccccccccccccccccccccccciiinntttxxxwwwyyywwvvvvrqqjjjjdddccc
+abcccccccccccccccccccccccccccaaaaaaccccccccccccccccccccccccccccccccccccccccccciinnntttxwwwwwyyywwvvvrrrqkkkeddcccc
+abcccccccccccccccccccccccccccaaaaaaccccccccccccccccccccccccccccccccccccccccccchhnnntttsswwswwyywwrrrrrrkkkkeeecccc
+abcccccccccccccccccccccccccccaaaaaacccccccccccccccccccaccccccccccccaaacccccccchhhnmmssssssswwwwwwrrrkkkkkeeeeecccc
+abcccccccccccccccccccccccccccccaaacccccccccccccccccccaaccccccccccaaaaaacccccaahhhmmmmmsssssswwwwrrrkkkkkeeeeeccccc
+abaacccccccccccccaccccccccccccccccccccccccccccccccaaaaacaacccccccaaaaaacaaaaaahhhhmmmmmmmmssswwwrrkkkkeeeeeacccccc
+abacccccccccccccaaaaaaaaccccccccaaacccccccaaccccccaaaaaaaacccccccaaaaaacaaaaaaahhhhmmmmmmmmsssrrrrkkkeeeeeaacccccc
+abaaaccccaaccccccaaaaaacccccccccaaacccaacaaaccccccccaaaacccccccccaaaaacccaaaaaaahhhhhhhmmmmlsssrrllkfeeeeaaaaacccc
+abaaaccaaaaccccccaaaaaacccccccccaaaaaaaaaaaaaacccccaaaaacccccccccaaaaacccaaaaaaachhhhhgggmllsssrrllkffeaaaaaaacccc
+abaacccaaaaaacccaaaaaaaacccccaaaaaaaaaaaaaaaaacccccaacaaacccccccccccccccaaaaaacccccchggggglllllllllfffaaaaaaaacccc
+abaaccccaaaacccaaaaaaaaaaccccaaaaaaaaacaaaaaaaccaccaccaaacccccccccccccccaaaaaacccccccccgggglllllllffffaaaaaacccccc
+abcccccaaaaacccaaaaaaaaaacccccaaaaaaaccaaaaacccaaaccccccccccccccccccccccccccaacccccccccagggglllllffffccccaaacccccc
+abcccccaacaaccccccaaaaacaccaacccaaaaaaaaaaaaaccaaacccccccccccccccccccccccccccccccccccccaagggggffffffcccccccccccccc
+abcccccccccccaaaaaaaaacccccaaccaaaaaaaccaaaaacaaaaccccccccccccccccccccccccccccccccccccaaaacgggfffffccccccccccccccc
+abcccccccccccaaaaacaacccaaaaaaaaaaccaacccaaaaaaaacccaaccccccccccccccccccccccccccccccccccccccggfffccccccccccccaaaca
+abccccccccccaaaaaaccccccaaaaaaaaacccccccccaaaaaaaaaaaacccccccccccccaaaccccccccccccccccccccccaaaccccccccccccccaaaaa
+abccccccccccaaaaaaccccccccaaaacccccccccccccaaaaaaaaaaaaccccccccccccaaaaccccccccccccccccccccccaaaccccccccccccccaaaa
+abcccccccccccaaaaacccccccaaaaaaccccccccccaaaaaaaaaaaaaaccccccccccccaaaaccccccccccccccccccccccccccccccccccccccaaaaa

2022/inputs/day12.test

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+Sabqponm
+abcryxxl
+accszExk
+acctuvwj
+abdefghi