Groups > comp.lang.java.programmer > #3984

Re: Did the sort do anything?

From	Robert Klemme <shortcutter@googlemail.com>
Newsgroups	comp.lang.java.programmer
Subject	Re: Did the sort do anything?
Date	2011-05-11 20:40 +0200
Message-ID	<9303hcFq0nU1@mid.individual.net> (permalink)
References	<eskis656eeu0of5f5do1ogdpfbdau3d06i@4ax.com>

Show all headers | View raw

On 05/10/2011 05:06 PM, Roedy Green wrote:
> Often you sort things when they are already sorted.
>
> I am interested in simple algorithms to detect whether the sort
> actually did anything.

What would the benefit of this be?  When you learn the fact the current 
sorting run has been done already.  And the data tells you nothing about 
what future sorts will do.  OK, you know, they won't do anything if you 
do not modify the collection / array.  But you did know that before, 
didn't you?  And if you insert in sort order then you also know that 
there is no additional sort necessary.  If you pull the data from some 
external source you also do not know whether next time round you need to 
sort.  So what is this information useful for?

Btw, couldn't option 3 be tricky?  Depending on the sorting algorithm 
things might be moved around but the final order might be the same as 
before.  Not that this would be desirable but I am pretty sure there are 
sorting algorithms which have this property (probably quicksort).  Now, 
how then do you interpret your boolean flag?  Basically you only know 
sequences are identical if there was no movement whatsoever, but if 
there was movement then you do not know.  Which means you would need to 
apply one of the other strategies additionally...

Kind regards

	robert

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

Thread

Did the sort do anything? Roedy Green <see_website@mindprod.com.invalid> - 2011-05-10 08:06 -0700
  Re: Did the sort do anything? markspace <-@.> - 2011-05-10 08:48 -0700
    Re: Did the sort do anything? Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-05-14 15:33 +1200
      Re: Did the sort do anything? Lew <noone@lewscanon.com> - 2011-05-14 08:56 -0400
        Re: Did the sort do anything? Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-05-14 13:54 +0000
          Re: Did the sort do anything? Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-05-15 11:16 +1200
      Re: Did the sort do anything? Lew <noone@lewscanon.com> - 2011-05-14 23:24 -0400
        Re: Did the sort do anything? Tom Anderson <twic@urchin.earth.li> - 2011-05-15 11:20 +0100
          Re: Did the sort do anything? Lew <noone@lewscanon.com> - 2011-05-15 07:00 -0400
            Re: Did the sort do anything? Tom Anderson <twic@urchin.earth.li> - 2011-05-15 15:09 +0100
              Re: Did the sort do anything? Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-05-16 14:28 +1200
                Re: Did the sort do anything? Joshua Cranmer <Pidgeot18@verizon.invalid> - 2011-05-15 22:38 -0400
                Re: Did the sort do anything? Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-05-16 19:11 +1200
                Re: Did the sort do anything? Lew <noone@lewscanon.com> - 2011-05-16 03:47 -0400
                Re: Did the sort do anything? markspace <-@.> - 2011-05-16 14:14 -0700
                Re: Did the sort do anything? Lew <noone@lewscanon.com> - 2011-05-15 22:40 -0400
                Re: Did the sort do anything? Tom Anderson <twic@urchin.earth.li> - 2011-05-16 21:31 +0100
                Re: Did the sort do anything? Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-05-17 09:12 +1200
                Re: Did the sort do anything? Lew <noone@lewscanon.com> - 2011-05-16 17:24 -0400
                Re: Did the sort do anything? Tom Anderson <twic@urchin.earth.li> - 2011-05-17 13:26 +0100
          Re: Did the sort do anything? markspace <-@.> - 2011-05-15 04:56 -0700
            Re: Did the sort do anything? Tom Anderson <twic@urchin.earth.li> - 2011-05-15 15:12 +0100
              Re: Did the sort do anything? markspace <-@.> - 2011-05-15 07:52 -0700
          Re: Did the sort do anything? Michael Wojcik <mwojcik@newsguy.com> - 2011-05-18 11:14 -0400
            Re: Did the sort do anything? Lew <noone@lewscanon.com> - 2011-05-18 13:02 -0400
            Re: Did the sort do anything? Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-05-20 18:49 +1200
              Re: Did the sort do anything? Robert Klemme <shortcutter@googlemail.com> - 2011-05-20 00:06 -0700
                Re: Did the sort do anything? Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-05-20 22:37 +1200
                Re: Did the sort do anything? Lew <noone@lewscanon.com> - 2011-05-20 07:09 -0400
  Re: Did the sort do anything? Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-05-10 16:11 +0000
  Re: Did the sort do anything? Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-05-10 21:26 +0200
    Re: Did the sort do anything? Tom Anderson <twic@urchin.earth.li> - 2011-05-11 21:38 +0100
      Re: Did the sort do anything? Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-05-11 23:27 +0200
      Re: Did the sort do anything? Roedy Green <see_website@mindprod.com.invalid> - 2011-05-13 07:40 -0700
        Re: Did the sort do anything? Spock <spock@starfleet.ufp> - 2011-05-13 16:56 -0400
        Re: Did the sort do anything? Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-05-15 13:58 +1200
          Re: Did the sort do anything? Lew <noone@lewscanon.com> - 2011-05-14 23:27 -0400
  Re: Did the sort do anything? Robert Klemme <shortcutter@googlemail.com> - 2011-05-11 20:40 +0200
    Re: Did the sort do anything? Joshua Cranmer <Pidgeot18@verizon.invalid> - 2011-05-12 10:40 -0400
      Re: Did the sort do anything? Robert Klemme <shortcutter@googlemail.com> - 2011-05-13 03:50 -0700
      Re: Did the sort do anything? Roedy Green <see_website@mindprod.com.invalid> - 2011-05-13 07:46 -0700
        Re: Did the sort do anything? Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-05-16 14:32 +1200
          Re: Did the sort do anything? Patricia Shanahan <pats@acm.org> - 2011-05-15 19:50 -0700
            Re: Did the sort do anything? Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-05-16 17:57 +1200
              Re: Did the sort do anything? "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2011-05-16 03:35 -0400
              Re: Did the sort do anything? Lew <noone@lewscanon.com> - 2011-05-16 03:44 -0400
              Re: Did the sort do anything? Patricia Shanahan <pats@acm.org> - 2011-05-16 03:53 -0700
                Re: Did the sort do anything? Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-05-17 00:02 +1200
                Re: Did the sort do anything? "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2011-05-16 08:05 -0400
                Re: Did the sort do anything? Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-05-17 09:12 +1200
                Re: Did the sort do anything? Lew <noone@lewscanon.com> - 2011-05-16 17:32 -0400
                Re: Did the sort do anything? thoolen <thoolen@tholenbot.thorium> - 2011-05-16 18:09 -0400
                Re: Did the sort do anything? Lew <noone@lewscanon.com> - 2011-05-16 10:02 -0400
                Re: Did the sort do anything? Patricia Shanahan <pats@acm.org> - 2011-05-16 07:16 -0700
                Re: Did the sort do anything? Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-05-17 09:11 +1200
                Re: Did the sort do anything? Patricia Shanahan <pats@acm.org> - 2011-05-16 15:00 -0700
                Re: Did the sort do anything? Lew <noone@lewscanon.com> - 2011-05-16 21:08 -0400
                Re: Did the sort do anything? Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-05-17 19:11 +1200
                Re: Did the sort do anything? Patricia Shanahan <pats@acm.org> - 2011-05-17 02:34 -0700
                Re: Did the sort do anything? Lew <noone@lewscanon.com> - 2011-05-17 07:19 -0400
                [OT] Naming conventions. Was: Re: Did the sort do anything? Patricia Shanahan <pats@acm.org> - 2011-05-17 06:52 -0700
                Re: Naming conventions. Was: Re: Did the sort do anything? Robert Klemme <shortcutter@googlemail.com> - 2011-05-18 01:22 -0700
                Re: Naming conventions. Was: Re: Did the sort do anything? Patricia Shanahan <pats@acm.org> - 2011-05-18 03:42 -0700
                Re: Naming conventions. Was: Re: Did the sort do anything? RedGrittyBrick <RedGrittyBrick@spamweary.invalid> - 2011-05-18 11:53 +0100
                Re: Naming conventions. Was: Re: Did the sort do anything? Lew <noone@lewscanon.com> - 2011-05-18 13:07 -0400
                Re: Naming conventions. Was: Re: Did the sort do anything? Patricia Shanahan <pats@acm.org> - 2011-05-18 10:37 -0700
                Re: Naming conventions. Was: Re: Did the sort do anything? Heike Svensson <hsvensson.1093x1_q@hotmail.nospam.com.please> - 2011-05-19 01:29 -0400
                Re: Naming conventions. Was: Re: Did the sort do anything? Robert Klemme <shortcutter@googlemail.com> - 2011-05-19 08:28 +0200
                Re: Naming conventions. Was: Re: Did the sort do anything? Lew <noone@lewscanon.com> - 2011-05-19 08:50 -0400
                OT: National stereotypes. Was Re: Naming conventions. Was: Re: Did the sort do anything? RedGrittyBrick <RedGrittyBrick@spamweary.invalid> - 2011-05-23 10:25 +0100
                Re: OT: National stereotypes. Was Re: Naming conventions. Was: Re: Did the sort do anything? Lew <noone@lewscanon.com> - 2011-05-23 09:05 -0400
                Re: OT: National stereotypes. Was Re: Naming conventions. Was: Re: Did the sort do anything? RedGrittyBrick <RedGrittyBrick@spamweary.invalid> - 2011-05-23 17:17 +0100
                Re: OT: National stereotypes. Was Re: Naming conventions. Was: Re: Did the sort do anything? Lew <noone@lewscanon.com> - 2011-05-23 14:43 -0400
                Re: OT: National stereotypes. Was Re: Naming conventions. Was: Re: Did the sort do anything? Steve Sobol <sjsobol@JustThe.net> - 2011-05-23 08:27 -0700
                Re: OT: National stereotypes. Was Re: Naming conventions. Was: Re: Did the sort do anything? RedGrittyBrick <RedGrittyBrick@spamweary.invalid> - 2011-05-23 17:39 +0100
                Re: OT: National stereotypes. Was Re: Naming conventions. Was: Re:   Did the sort do anything? Robert Klemme <shortcutter@googlemail.com> - 2011-05-23 19:16 +0200
                Re: OT: National stereotypes. Was Re: Naming conventions. Was: Re: Did the sort do anything? Lew <noone@lewscanon.com> - 2011-05-23 14:47 -0400
                Re: Did the sort do anything? Boojum <boojum42@gmai1.c0m> - 2011-05-18 07:19 -0400
                Re: Did the sort do anything? Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-05-20 18:46 +1200
                Re: Did the sort do anything? Lew <noone@lewscanon.com> - 2011-05-20 07:10 -0400
                Re: Did the sort do anything? Lew <noone@lewscanon.com> - 2011-05-17 07:16 -0400
                Re: Did the sort do anything? Patricia Shanahan <pats@acm.org> - 2011-05-17 06:56 -0700
                Re: Did the sort do anything? Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-05-20 18:46 +1200
                Re: Did the sort do anything? Lew <noone@lewscanon.com> - 2011-05-20 07:11 -0400
                Re: Did the sort do anything? Patricia Shanahan <pats@acm.org> - 2011-05-20 05:00 -0700
                Re: Did the sort do anything? Patricia Shanahan <pats@acm.org> - 2011-05-20 05:20 -0700
                Re: Did the sort do anything? Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-05-21 09:56 +1200
                Re: Did the sort do anything? Lew <noone@lewscanon.com> - 2011-05-20 18:12 -0400
                Re: Did the sort do anything? Patricia Shanahan <pats@acm.org> - 2011-05-20 21:26 -0700
                Re: Did the sort do anything? Gheerax IV <gheerax.4@gmail.invalid> - 2011-05-17 06:58 +0000
                Re: Did the sort do anything? Unitary Matrix <umatrix668@gmail.com> - 2011-05-17 00:13 -0700
                Re: Did the sort do anything? markspace <-@.> - 2011-05-17 07:41 -0700
    Re: Did the sort do anything? Roedy Green <see_website@mindprod.com.invalid> - 2011-05-13 07:42 -0700
      Re: Did the sort do anything? Robert Klemme <shortcutter@googlemail.com> - 2011-05-13 21:28 +0200
  Re: Did the sort do anything? Tom Anderson <twic@urchin.earth.li> - 2011-05-11 21:32 +0100

csiph-web