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Re: Reverse sorting an array

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On 9/30/2011 6:24 PM, Fred wrote:
> Eric Sosman<esos...@ieee-dot-org.invalid>  wrote:
>>[...]
>>       What problem are you trying to solve?
>
> I want to sort the array of integers in descending order.

     Okay.  (That wasn't clear from your original post, where the
array in question contained fifty zeroes and was already sorted in
both ascending *and* descending order with no further effort!)

     As far as I know, Java has no built-in solution.  But there are
a few rather simple things you could do:

     * Use Arrays.sort() to put the array in ascending order, and then
       reverse it with a simple loop (swap [0]<=>[n-1], [1]<=>[n-2],
       and so on).

     * Use Arrays.sort() to put the array in ascending order, and then
       read it "backwards:" Instead of looking at [0],[1],[2],... you
       look at [n-1],[n-2],[n-3],...

     * Negate every element of the array, use Arrays.sort() to put the
       array in ascending order, and then negate all the elements again.
       (Note that this won't work if Integer.MIN_VALUE appears in the
       array, because Integer.MIN_VALUE == -Integer.MIN_VALUE.)

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

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Thread

Reverse sorting an array Fred <albert.xtheunknown0@gmail.com> - 2011-09-30 04:03 -0700
  Re: Reverse sorting an array Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-09-30 07:50 -0400
    Re: Reverse sorting an array Fred <albert.xtheunknown0@gmail.com> - 2011-09-30 15:24 -0700
      Re: Reverse sorting an array Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-09-30 20:50 -0400
        Re: Reverse sorting an array Roedy Green <see_website@mindprod.com.invalid> - 2011-10-01 19:38 -0700
          Re: Reverse sorting an array Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-10-01 22:58 -0400
            Re: Reverse sorting an array Lew <lewbloch@gmail.com> - 2011-10-01 20:21 -0700
    Re: Reverse sorting an array Fred <albert.xtheunknown0@gmail.com> - 2011-09-30 15:31 -0700
      Re: Reverse sorting an array Roedy Green <see_website@mindprod.com.invalid> - 2011-09-30 15:45 -0700
        Re: Reverse sorting an array Fred <albert.xtheunknown0@gmail.com> - 2011-09-30 16:27 -0700
          Re: Reverse sorting an array Patricia Shanahan <pats@acm.org> - 2011-09-30 16:58 -0700
    Re: Reverse sorting an array Roedy Green <see_website@mindprod.com.invalid> - 2011-09-30 15:43 -0700
      Re: Reverse sorting an array Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-09-30 20:57 -0400
  Re: Reverse sorting an array Roedy Green <see_website@mindprod.com.invalid> - 2011-09-30 04:58 -0700
    What qualifies as a constant ? (Was: Reverse sorting an array) Mayeul <mayeul.marguet@free.fr> - 2011-09-30 14:45 +0200
      Re: What qualifies as a constant ? (Was: Reverse sorting an array) Lew <lewbloch@gmail.com> - 2011-09-30 07:39 -0700
        Re: What qualifies as a constant ? (Was: Reverse sorting an array) Mayeul <mayeul.marguet@free.fr> - 2011-09-30 17:15 +0200
          Re: What qualifies as a constant ? (Was: Reverse sorting an array) Lew <lewbloch@gmail.com> - 2011-09-30 08:42 -0700

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