Re: [Haskell-cafe] Re: Function to detect duplicates

Am Dienstag 23 Februar 2010 13:59:49 schrieb Ertugrul Soeylemez:

Jonas Almström Duregård wrote:

...

Ertugrul: while your solution is minimalistic, Rafael deemed his ~n*log n implementation too inefficient. Thus your ~n^3 implementation is hardly an improvement...

Not quite as bad, nub is O(n^2).

My variant has an advantage, though. It is completely lazy, so it will take a shortcut, as soon as a duplicate is found. Depending on his application, this may be useful or not.

I think the nub-based solution is the best one in general, but it's the base library implementation of nub, which is unfortunate. In fact, with a better nub implementation, this becomes an O(n * log n) time

How can you nub in O(n*log n)? Remember, you only have Eq for nub.

algorithm, too, but with the additional laziness advantage. The article you linked to contains such an implementation, I think.

Greets Ertugrul