Groups > comp.lang.java.programmer > #7943

Re: Using Java Classes to Sort a Small Array Quickly

From	Eric Sosman <esosman@ieee-dot-org.invalid>
Newsgroups	comp.lang.java.programmer
Subject	Re: Using Java Classes to Sort a Small Array Quickly
Date	2011-09-12 21:29 -0400
Organization	A noiseless patient Spider
Message-ID	<j4mblo$p46$1@dont-email.me> (permalink)
References	(2 earlier) <MPG.28d742f5c91d21e9896b8@202.177.16.121> <j4jala$dkh$1@dont-email.me> <MPG.28d76557830521d69896ba@202.177.16.121> <fuhs67lrl26ubtv16brfg56c4kueldb28k@4ax.com> <4e6e8f47$0$308$14726298@news.sunsite.dk>

Show all headers | View raw

On 9/12/2011 7:01 PM, Arne Vajhøj wrote:
> On 9/12/2011 1:57 PM, Gene Wirchenko wrote:
>> On Mon, 12 Sep 2011 01:40:50 +0200, Wanja Gayk<brixomatic@yahoo.com>
>> wrote:
>>> In article<j4jala$dkh$1@dont-email.me>, esosman@ieee-dot-org.invalid
>>> says...
>>>
>>>> Very nice! Would you care to try this approach on a shorter
>>>> input array, like
>>>>
>>>> data = new int[] { Integer.MAX_VALUE };
>>>>
>>>> This case should be quite simple, since the array is already sorted.
>>>> Let us know how you make out, will you?
>>>
>>> I didn't say it works for any array out there, did I?
>>
>> You did. Claiming an algorithm is O(n) means claiming that that
>> is the upper bound.
>
> No - big O for algorithms is usual average case not worst case.

     Big O is for whatever quantity it is measuring.

> I am sure you can find plenty of quotes for quicksort being
> O(nlogn) and not O(n^2).

     Quicksort takes O(n*log n) *average* time, O(n*n) *worst case*
time.  Neither of the Big O's is in any way "preferable" to the
other: They are describing different aspects of the algorithm.
There is no reason to *expect* "average time" and "worst case time"
and "time off for good behavior" to have similar Big-O expressions.

-- 
Eric Sosman
esosman@ieee-dot-org.invalid

Back to comp.lang.java.programmer | Previous | Next — Previous in thread | Next in thread | Find similar

Thread

Using Java Classes to Sort a Small Array Quickly KevinSimonson <kvnsmnsn@hotmail.com> - 2011-08-31 19:48 -0700
  Re: Using Java Classes to Sort a Small Array Quickly markspace <-@.> - 2011-08-31 20:39 -0700
    Re: Using Java Classes to Sort a Small Array Quickly bugbear <bugbear@trim_papermule.co.uk_trim> - 2011-09-01 09:18 +0100
    Re: Using Java Classes to Sort a Small Array Quickly Roedy Green <see_website@mindprod.com.invalid> - 2011-09-01 02:38 -0700
      Re: Using Java Classes to Sort a Small Array Quickly Patricia Shanahan <pats@acm.org> - 2011-09-01 03:50 -0700
    Re: Using Java Classes to Sort a Small Array Quickly Wanja Gayk <brixomatic@yahoo.com> - 2011-09-11 23:14 +0200
      Re: Using Java Classes to Sort a Small Array Quickly Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-09-11 17:53 -0400
        Re: Using Java Classes to Sort a Small Array Quickly Wanja Gayk <brixomatic@yahoo.com> - 2011-09-12 01:40 +0200
          Re: Using Java Classes to Sort a Small Array Quickly Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-09-11 20:32 -0400
            Re: Using Java Classes to Sort a Small Array Quickly Wanja Gayk <brixomatic@yahoo.com> - 2011-09-17 02:54 +0200
              Re: Using Java Classes to Sort a Small Array Quickly Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-09-16 21:03 -0400
                Re: Using Java Classes to Sort a Small Array Quickly Wanja Gayk <brixomatic@yahoo.com> - 2011-09-17 16:52 +0200
                Re: Using Java Classes to Sort a Small Array Quickly Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-09-17 11:05 -0400
                Re: Using Java Classes to Sort a Small Array Quickly Wanja Gayk <brixomatic@yahoo.com> - 2011-09-18 15:41 +0200
                Re: Using Java Classes to Sort a Small Array Quickly Lew <lewbloch@gmail.com> - 2011-09-18 12:53 -0700
                Re: Using Java Classes to Sort a Small Array Quickly Patricia Shanahan <pats@acm.org> - 2011-09-18 13:20 -0700
          Re: Using Java Classes to Sort a Small Array Quickly Arne Vajhøj <arne@vajhoej.dk> - 2011-09-11 21:10 -0400
            Re: Using Java Classes to Sort a Small Array Quickly Lew <lewbloch@gmail.com> - 2011-09-11 20:30 -0700
              Re: Using Java Classes to Sort a Small Array Quickly Arne Vajhøj <arne@vajhoej.dk> - 2011-09-12 19:13 -0400
                Re: Using Java Classes to Sort a Small Array Quickly Lew <lewbloch@gmail.com> - 2011-09-12 17:42 -0700
                Re: Using Java Classes to Sort a Small Array Quickly Wanja Gayk <brixomatic@yahoo.com> - 2011-09-17 02:54 +0200
                Re: Using Java Classes to Sort a Small Array Quickly Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-09-16 21:13 -0400
                Re: Using Java Classes to Sort a Small Array Quickly Patricia Shanahan <pats@acm.org> - 2011-09-16 23:14 -0700
                Re: Using Java Classes to Sort a Small Array Quickly Wanja Gayk <brixomatic@yahoo.com> - 2011-09-17 16:53 +0200
                Re: Using Java Classes to Sort a Small Array Quickly Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-09-12 21:24 -0400
          Re: Using Java Classes to Sort a Small Array Quickly Gene Wirchenko <genew@ocis.net> - 2011-09-12 10:57 -0700
            Re: Using Java Classes to Sort a Small Array Quickly Arne Vajhøj <arne@vajhoej.dk> - 2011-09-12 19:01 -0400
              Re: Using Java Classes to Sort a Small Array Quickly Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-09-12 21:29 -0400
                Re: Using Java Classes to Sort a Small Array Quickly markspace <-@.> - 2011-09-12 19:49 -0700
                Re: Using Java Classes to Sort a Small Array Quickly Lew <lewbloch@gmail.com> - 2011-09-12 21:51 -0700
                Re: Using Java Classes to Sort a Small Array Quickly Joshua Cranmer <Pidgeot18@verizon.invalid> - 2011-09-13 11:32 -0500
                Re: Using Java Classes to Sort a Small Array Quickly Arne Vajhøj <arne@vajhoej.dk> - 2011-09-13 21:51 -0400
                Re: Using Java Classes to Sort a Small Array Quickly Gene Wirchenko <genew@ocis.net> - 2011-09-14 11:00 -0700
                Re: Using Java Classes to Sort a Small Array Quickly Patricia Shanahan <pats@acm.org> - 2011-09-13 06:33 -0700
              Re: Using Java Classes to Sort a Small Array Quickly Gene Wirchenko <genew@ocis.net> - 2011-09-13 09:48 -0700
  Re: Using Java Classes to Sort a Small Array Quickly Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-09-01 00:25 -0400
    Re: Using Java Classes to Sort a Small Array Quickly Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-09-01 00:54 -0400
    Re: Using Java Classes to Sort a Small Array Quickly bugbear <bugbear@trim_papermule.co.uk_trim> - 2011-09-01 09:20 +0100
      Re: Using Java Classes to Sort a Small Array Quickly Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-09-01 08:06 -0400
    Re: Using Java Classes to Sort a Small Array Quickly Roedy Green <see_website@mindprod.com.invalid> - 2011-09-01 02:43 -0700
  Re: Using Java Classes to Sort a Small Array Quickly Robert Klemme <shortcutter@googlemail.com> - 2011-09-01 08:32 +0200
  Re: Using Java Classes to Sort a Small Array Quickly RedGrittyBrick <RedGrittyBrick@spamweary.invalid> - 2011-09-01 10:08 +0100
    Re: Using Java Classes to Sort a Small Array Quickly Patricia Shanahan <pats@acm.org> - 2011-09-01 04:02 -0700
  Re: Using Java Classes to Sort a Small Array Quickly Roedy Green <see_website@mindprod.com.invalid> - 2011-09-01 02:37 -0700
  Re: Using Java Classes to Sort a Small Array Quickly Roedy Green <see_website@mindprod.com.invalid> - 2011-09-01 04:53 -0700
  Re: Using Java Classes to Sort a Small Array Quickly Joshua Cranmer <Pidgeot18@verizon.invalid> - 2011-09-01 09:05 -0500

csiph-web