Alternatively, the definition of your tree could include a list of linked lists, one for each level of the tree. Then you could just select the last list and it's the same as saving only the leaves from a complete inorder walk of the tree. data AltTree a = AltTree { tree_structure :: Tree a, nodes :: [[a]] } On Wednesday 21 February 2007 14:31, Tom Hawkins wrote:
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 _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe