Re: No merge sort?
От | Dann Corbit |
---|---|
Тема | Re: No merge sort? |
Дата | |
Msg-id | D90A5A6C612A39408103E6ECDD77B8294CDACF@voyager.corporate.connx.com обсуждение исходный текст |
Ответ на | No merge sort? (Taral <taral@taral.net>) |
Список | pgsql-hackers |
> -----Original Message----- > From: Steve Wampler [mailto:swampler@noao.edu] > Sent: Monday, April 07, 2003 1:58 PM > To: Dann Corbit > Cc: Jason M. Felice; Postgres-hackers > Subject: Re: [HACKERS] No merge sort? > On Mon, 2003-04-07 at 13:39, Dann Corbit wrote: > > > -----Original Message----- > > > From: Jason M. Felice [mailto:jfelice@cronosys.com] > > > Sent: Monday, April 07, 2003 1:10 PM > > > To: pgsql-hackers@postgresql.org > > > Subject: Re: [HACKERS] No merge sort? > > > > > > > > > On Mon, Apr 07, 2003 at 03:36:10PM -0400, Greg Stark wrote: > > > > "Ron Peacetree" <rjpeace@earthlink.net> writes: > > > > > > > > > AFAIK, there are only 3 general purpose internal sorting > > > techniques > > > > > that have O(n) behavior: > > > > > > > > Strictly speaking there are no sorting algorithms that have > > > worst-case > > > > time behaviour better than O(nlog(n)). Period. > > > > > > > > > > Not true. > > > > > http://www.elsewhere.org/jargon/html/entry/bogo-sort.html > > > > He said "better than" not "worse than". > > > > For comparison based sorting it is _provably_ true that you cannot > > sort faster than log(n!) which is O(n*(log(n))). > > You didn't read far enough. The 2nd form of the bogo sort is > O(1), at least in *one* universe... An array holding all possible outcomes is an implementation of this algorithm. Quite frankly, it's rather silly (as it is intended to be).
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