Tom, I think inserting elements would be a lot faster than multiple unions. I would try: leafList :: Tree -> [Int] leafList (Leaf n) = [n] leafList (Branch left right) = leafList left ++ leafList right leaves = fromList . leafList If you're writing many functions on Trees (or maybe even if you're not), you might consider writing a fold function and putting leafList in terms of this. Do you have experience with folds? -Chad
Hello,
Any recommendations for speeding up extracting the set of leaves from a tree?
data Tree = Branch Tree Tree | Leaf Int deriving (Eq, Ord)
My slow, naive function:
leaves :: Tree -> Set Int leaves (Leaf n) = singleton n leaves (Branch left right) = union (leaves left) (leaves right)
In my case, many of the branches in the tree are the same. I suspect the fixed point operation mentioned in the thread "speeding up fibonacci with memoizing" is applicable, but I'm having a tough time making the connection.
-Tom