Subject: Re: [boost] [Countertree + Suballocator] New Version
From: Thomas Klimpel (Thomas.Klimpel_at_[hidden])
Date: 2012-04-12 14:30:08
Dave Abrahams wrote:
> on Thu Apr 12 2012, Francisco JosÃ© Tapia <fjtapia-AT-gmail.com> wrote:
> > The iterators are random access , and you can subtract two iterators in
> > a O(log N) time for to know the number of nodes between them (even with
> > the end( ) and rend( ) iterators)
> If by "are random access" you mean they satisfy the random access
> iterator requirements, then this is a contradiction. Iterator
> subtraction is required to be O(1) for random access iterators.
If the container can store at most 2^64 elements, it can be hard to distinguish O(1) from O(log N). However, if O(log N) implies cache misses and swapping, then O(log N) may really be different from O(1) in practice.
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