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Groups > comp.lang.java.programmer > #10423
| Date | 2011-12-02 05:58 -0800 |
|---|---|
| From | Patricia Shanahan <pats@acm.org> |
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: Verifying a list is alphabetized |
| References | <722147ec-ab43-4d7c-8b41-32f8705ee7db@i8g2000vbh.googlegroups.com> <207hd7h05rmodleca7qv41h73luek13qmm@4ax.com> |
| Message-ID | <LKmdnf5NRegdREXTnZ2dnUVZ_rudnZ2d@earthlink.com> (permalink) |
On 12/2/2011 1:43 AM, Roedy Green wrote:
> On Wed, 30 Nov 2011 07:52:49 -0800 (PST), laredotornado
> <laredotornado@zipmail.com> wrote, quoted or indirectly quoted someone
> who said :
>
>> I'm using Java 1.6. Given a java.util.List of Strings, what is the
>> quickest way to verify that the list is sorted in ascending order?
...
> /**
> * Is this List already in order according to its Comparable
> interface?
> *
> * @param list List of Comparable objects.
> *
> * @return true if array already in order.
> */
> public static <T extends Comparable<? super T>> boolean inOrder(
> List<T> list )
> {
> final int length = list.size();
> for ( int i = 1; i < length; i++ )
> {
> if ( list.get( i ).compareTo( list.get( i - 1 ) ) < 0 )
> {
> return false;
> }
> }
> return true;
> }
This will not be the quickest way unless the List happens to have fast
indexed access. For a length N linked list, it will take O(N*N) time.
Generally, if you are scanning a List that is not known to implement
RandomAccess, it is better use Iterator-based methods as much as
possible. They are almost as fast as indexed access for RandomAccess
lists, and much faster for the other List implementations.
Patricia
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Verifying a list is alphabetized laredotornado <laredotornado@zipmail.com> - 2011-11-30 07:52 -0800
Re: Verifying a list is alphabetized Knute Johnson <nospam@knutejohnson.com> - 2011-11-30 08:05 -0800
Re: Verifying a list is alphabetized Lew <lewbloch@gmail.com> - 2011-11-30 11:18 -0800
Re: Verifying a list is alphabetized Arne Vajhøj <arne@vajhoej.dk> - 2011-12-02 19:54 -0500
Re: Verifying a list is alphabetized Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-12-03 07:44 -0500
Re: Verifying a list is alphabetized Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-12-03 09:02 -0500
Re: Verifying a list is alphabetized Roedy Green <see_website@mindprod.com.invalid> - 2011-12-03 20:05 -0800
Re: Verifying a list is alphabetized Roedy Green <see_website@mindprod.com.invalid> - 2011-12-03 22:13 -0800
Re: Verifying a list is alphabetized Tom Anderson <twic@urchin.earth.li> - 2011-12-04 21:47 +0000
Re: Verifying a list is alphabetized Martin Gregorie <martin@address-in-sig.invalid> - 2011-12-04 12:42 +0000
Re: Verifying a list is alphabetized Patricia Shanahan <pats@acm.org> - 2011-12-04 12:18 -0800
Re: Verifying a list is alphabetized Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2011-12-04 13:17 -0800
Re: Verifying a list is alphabetized Patricia Shanahan <pats@acm.org> - 2011-12-04 15:32 -0800
Re: Verifying a list is alphabetized markspace <-@.> - 2011-12-04 15:59 -0800
Re: Verifying a list is alphabetized Patricia Shanahan <pats@acm.org> - 2011-12-04 16:14 -0800
Re: Verifying a list is alphabetized markspace <-@.> - 2011-12-04 17:12 -0800
Re: Verifying a list is alphabetized Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-12-04 21:17 -0500
Re: Verifying a list is alphabetized Tom Anderson <twic@urchin.earth.li> - 2011-12-04 22:11 +0000
Re: Verifying a list is alphabetized Martin Gregorie <martin@address-in-sig.invalid> - 2011-12-04 23:41 +0000
Re: Verifying a list is alphabetized Roedy Green <see_website@mindprod.com.invalid> - 2011-12-12 01:39 -0800
Re: Verifying a list is alphabetized Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-12-04 08:47 -0500
Re: Verifying a list is alphabetized Gene Wirchenko <genew@ocis.net> - 2011-12-04 21:34 -0800
Re: Verifying a list is alphabetized Patricia Shanahan <pats@acm.org> - 2011-11-30 12:52 -0800
Re: Verifying a list is alphabetized laredotornado <laredotornado@zipmail.com> - 2011-12-01 06:43 -0800
Re: Verifying a list is alphabetized Joshua Maurice <joshuamaurice@gmail.com> - 2011-11-30 13:16 -0800
Re: Verifying a list is alphabetized Roedy Green <see_website@mindprod.com.invalid> - 2011-12-02 01:43 -0800
Re: Verifying a list is alphabetized Patricia Shanahan <pats@acm.org> - 2011-12-02 05:58 -0800
Re: Verifying a list is alphabetized Arne Vajhøj <arne@vajhoej.dk> - 2011-12-02 19:55 -0500
Re: Verifying a list is alphabetized Roedy Green <see_website@mindprod.com.invalid> - 2011-12-03 02:54 -0800
Re: Verifying a list is alphabetized Patricia Shanahan <pats@acm.org> - 2011-12-03 06:17 -0800
Re: Verifying a list is alphabetized Roedy Green <see_website@mindprod.com.invalid> - 2011-12-03 03:10 -0800
Re: Verifying a list is alphabetized Arne Vajhøj <arne@vajhoej.dk> - 2011-12-02 19:52 -0500
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