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From: Ian Collins <ian-news@hotmail.com>
Newsgroups: comp.lang.c
Subject: Re: So here's a fun challenge
Date: Sun, 3 Nov 2019 18:02:43 +1300
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Xref: csiph.com comp.lang.c:147526

On 03/11/2019 17:18, DFS wrote:
> On 11/2/2019 9:35 PM, Ian Collins wrote:

>> ZZZzN3DyoJU9hOy
>> ZZZZhpliD
>> ZzzzgdAwKww
>> zzZZ4waPKAofj
>> ZzZYshGXMOzI
>> zZzyp0NY0
>> zZzyo7v3
>> ZzzYLx3l2Nmnc973
>> zzZydYrs3quxF
>> ZzZy6FpMdt1Zw
>>
>> real    0m4.744s
> 
> 
> Unbelievably quick.  Nearly 10x faster than mine.  I do have a senior
> citizen processor (i5-750@2.67GHz).
> 
> 
> But I see you didn't do a case-insensitive sort.
> 
>   > ZZZzN3DyoJU9hOy
>   > ZZZZhpliD
> 
> 
> 3/4 of the proc time in my code is qsorting, which does untold
> strcasecmp's - that's where the slowdown is.
> 

That's odd - the other are in order - Ah!  The order of the tail is 
reversed ZZZzN3DyoJU9hOy is the last entry.

Your C version (modulo the windows stuff) gives:

1.4832s to create 10000000 random string elements (+ add dupes)
qsorting... 4.8799s
program ran in 7.0736s seconds

So removing dupes appears to be a hot-spot.

-- 
Ian.