Re: [Haskell-cafe] cost of List.// for Ord types?

On Fri, 3 Sep 2004, David Roundy wrote:

Hello,

I was wondering if the list diff operator \\ takes advantage of situations where the list data type is in class Ord, besides being in Eq. If it is only in Eq, then \\ must be O(n^2), while if it is in Ord, a O(nlogn) \\ can be written.

Is it a problem that can also be solved by a more sophisticated data structure like FiniteMap?