My read of your quoted text is "This has the same average time complexity as WAVL/red-black trees, but is a simpler algorithm", which puts the search/insert/delete time complexity at O(log(n)). Being top-down means log(n) time complexity since that's the lower bound on the height of the tree.
My read of your quoted text is "This has the same average time complexity as WAVL/red-black trees, but is a simpler algorithm", which puts the search/insert/delete time complexity at O(log(n)). Being top-down means log(n) time complexity since that's the lower bound on the height of the tree.