:: Bool -> a -> a -> a package:parameterized-utils

balanceL p l r returns a balanced tree for the sequence l ++ [p] ++ r. It assumes that l and r are close to being balanced, and that only l may contain too many elements.

balanceR p l r returns a balanced tree for the sequence l ++ [p] ++ r. It assumes that l and r are close to being balanced, and that only r may contain too many elements.

link is called to insert a key and value between two disjoint subtrees.