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List:       kde-core-devel
Subject:    Re: vectors vs. lists
From:       Waldo Bastian <bastian () kde ! org>
Date:       2004-02-19 12:17:29
Message-ID: 200402191317.29896.bastian () kde ! org
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On Thu February 19 2004 10:46, Marc Mutz wrote:
> It's really funny how STL-trained people default to std::vector<> in all
> their code, and you see std::list<> only very rarely, but you see
> QValueList used as a default in KDE/Qt, and in ways that involve
> indexing (O(n)! vs. O(1) in QVV). This loop, btw,:
>
> for ( int i = 0 ; i < list.count() ; ++i )
>    doSomethingWith( list[i] );
>
> is O(n^2).

No, it is O(n) as well, see the implementation of 
QGList::locate( uint index )

Which brings me to my next point: 
* Don't optimize without profiling / benchmarking, there is a real risk that 
you make matters worse, not better.

Cheers,
Waldo
- -- 
bastian@kde.org -=|[ SUSE, The Linux Desktop Experts ]|=- bastian@suse.com
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