Day 22

day22/Part2.hs

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+module Part2 where
+
+import Commons
+import qualified Data.Map.Strict as M
+import qualified Data.Set as S
+import Data.Foldable (maximumBy)
+import Data.Function (on)
+
+
+getFutureFall' :: Snapshot -> S.Set Brick -> S.Set Brick
+getFutureFall' s sFell =
+  let falling = getFalling s
+  in if null falling then sFell
+     else let fell = getFell s falling
+              newSFell = S.union (S.difference sFell (S.fromList $ map snd falling)) $ S.fromList $ map snd fell
+          in getFutureFall' (getPostFall s falling fell) newSFell
+
+getFutureFall :: Snapshot -> Brick -> S.Set Brick
+getFutureFall s b = let newSnapshot = M.difference s $ M.fromList $ map (\ c -> ((z c, y c, x c), b)) b
+                    in getFutureFall' newSnapshot S.empty
+
+getReactions :: Snapshot -> [S.Set Brick]
+getReactions s = S.toList $ S.fromList $ map (getFutureFall s) $ M.elems s