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From: Malcolm McLean <malcolm.arthur.mclean@gmail.com>
Newsgroups: comp.lang.c
Subject: Re: filling area by color atack safety
Date: Tue, 19 Mar 2024 12:06:13 +0000
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On 19/03/2024 06:10, Tim Rentsch wrote:
> Malcolm McLean <malcolm.arthur.mclean@gmail.com> writes:
> 
>> On 18/03/2024 18:36, Tim Rentsch wrote:
>>>
>>>
>>> It doesn't scale well.  In particular worst case performance
>>> scaling is worse than O(N) (as determined experimentally, not
>>> theoretically).
>>
>> Is that because the queue is being memmoved instead of using a
>> circular buffer when it gets towards the end?
> 
> I'm sure I don't know, and I'm astonished that you would ask.
> It's your code after all.  IMO it should simply be thrown out and
> re-written;  it pains me just to look at it, let alone to try to
> understand or fix it.

Yes, but I wrote it years ago. I can't remember why the value of 256 
pixels was put in. But I do remember why the queue isn't very efficient 
- for the small images I expected to be processed, I judged that the 
added complexity of maintaining a circular queue wouldn't be worth it, 
given that I wanted the routine to be leaf. However if you can somehow 
trigger catastrophic big O behaviour, it won't be a surprise.

-- 
Check out Basic Algorithms and my other books:
https://www.lulu.com/spotlight/bgy1mm