With catMaybes

diff --git a/advent05/Main.hs b/advent05/Main.hs
index 727822d430fb7f17d14aac9e4f40d526a7ddfe04..21daf434eb0f17035f9b4542a926e88e56235291 100644 (file)
--- a/advent05/Main.hs
+++ b/advent05/Main.hs
@@ -52,9 +52,7 @@ extractName (Crate c) = c
 
 makeWharf :: [[Maybe Crate]] -> [Int] -> Wharf
 makeWharf wharfLines colNames = M.fromList $ zip colNames wharfCols
-  where wharfCols = fmap (fmap fromJust)
-                  $ fmap (dropWhile isNothing) 
-                  $ transpose wharfLines
+  where wharfCols = fmap catMaybes $ transpose wharfLines
 
 applyMoves1 :: Wharf -> [Move] -> Wharf
 applyMoves1 wharf moves = foldl' applyMove1 wharf moves