Re: remove-duplicates performances

[Stefan Monnier]

> i just noticed that `remove-duplicates' is very slow.

It's using an O(N²) algorithm, so it's indeed slow for long lists.

> (setq A (let ((seq (loop for i from 1 to 10000 collect i)))
>           (append seq seq)))
> (1 2 3 4 5 6 7 8 9 10 1 2 ...)

For such long lists, I fully expect it to be slow.
But for short lists, the overhead of constructing a hash-table should
make the current code competitive.  Can you try and find out for which
lengths your code is better than the one we have?


        Stefan