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Subject: Re: Fast way to sort moves in movelist ? - Bubble Sort

Author: leonid

Date: 13:48:51 10/18/99

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On October 18, 1999 at 14:03:49, KarinsDad wrote:

>On October 16, 1999 at 07:59:32, leonid wrote:
>
>[snip]
>>
>>If somebogy will mention what is the "bubble sort" it will be appreciated.
>>
>>Leonid.
>
>A bubble sort partially sorts with each pass. Hence, the passes for sorting the
>characters AECFDB are:
>
>1  2  3  4  5  6
>
>A  A  A  A  A  A
>E  C  C  C  B  B
>C  E  D  B  C  C
>F  D  B  D  D  D
>D  B  E  E  E  E
>B  F  F  F  F  F
>
>Each field is compared with the next field and if larger, it is exchanged. And,
>optimizations can be done such as only searching through to the last exchange
>(such as for pass 4, you only need to do 3 comparisons since in pass 3, the E
>got placed into the 5th location). Note: in the example above, A does not get
>checked against B until the 6th pass, so although the data is actually sorted in
>5 passes, the 6th pass verifies it.
>
>Bubble sorts are very inefficient since they make so many comparisons and
>exchanges in memory, however, they are easy to code, so I often use them to do a
>sort when I do not know if I need to actually sort. If I find out I need to
>sort, I eventually replace the bubble sort with a more optimized sort.
>
>I'm sure Dann has a web page to point you to code.
>
>KarinsDad :)

Thanks for responding!

You already once helped me with your idea about bounds. It permitted me to speed
my "positional logic" around 10%.

Leonid.



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