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Re: Cookies in boxes - algorithmic challenge

From Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups comp.lang.c
Subject Re: Cookies in boxes - algorithmic challenge
Date 2026-04-11 04:27 -0700
Organization A noiseless patient Spider
Message-ID <86mrz9ag91.fsf@linuxsc.com> (permalink)
References <20260401163447.000052de@yahoo.com> <86tstlwjak.fsf@linuxsc.com> <20260408222330.00005cf8@yahoo.com> <865x5zbg10.fsf@linuxsc.com> <20260410161638.00007745@yahoo.com>

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Michael S <already5chosen@yahoo.com> writes:

> On Thu, 09 Apr 2026 21:22:51 -0700
> Tim Rentsch <tr.17687@z991.linuxsc.com> wrote:

(just a few short replies)

>> [...]
>>
>> At each level of recursion, do the following:
>>
>>    If the search depth is the number of boxes, longjmp()
>>
>>    Next find the cookie of cookies in the solution state at or
>>    above this level that has the smallest number of boxes.  Because
>>    the box count is held in the uppermost bits the 64-bit values can
>>    simply be directly compared, without any masking.
>
> Is it proven that this step helps?
> To me it sounds unnecessary.

My experience with backtracking algorithms tells me that
selecting a path where the number of possible choices is
smallest usually does a better job of finding a solution
quickly.

>> [...]
>>
>> I think that's it.  I hope it makes sense.
>
> It makes sense, but it looks to me as solution by exhausting, augmented
> by "smallest number of boxes" heuristic.
> It's not obvious [to me] without further thinking that the worst case is
> not very slow.

Several short responses.

I think "by exhaustion" is usually taken to mean an unguided
exploration of all alternatives, even ones that aren't plausible.
Backtracking isn't that.

Backtracking is recognized as a viable search strategy in lots
of different kinds of problems, including problems that are
known to be NP complete.  It has a good pedigree.

My goals in writing the program were to write a program that is
understandable, that does find solutions, and that has reasonable
performance.  Since the program did find answers and also met your
stated performance goals, I have no reason to be dissatisfied.

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Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-01 16:34 +0300
  Re: Cookies in boxes - algorithmic challenge DFS <nospam@dfs.com> - 2026-04-01 10:02 -0400
    Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-01 17:15 +0300
      Re: Cookies in boxes - algorithmic challenge DFS <nospam@dfs.com> - 2026-04-01 10:28 -0400
        Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-01 17:58 +0300
  Re: Cookies in boxes - algorithmic challenge Bart <bc@freeuk.com> - 2026-04-01 15:20 +0100
    Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-01 17:56 +0300
      Re: Cookies in boxes - algorithmic challenge Bart <bc@freeuk.com> - 2026-04-01 19:50 +0100
        Re: Cookies in boxes - algorithmic challenge DFS <nospam@dfs.com> - 2026-04-01 15:56 -0400
          Re: Cookies in boxes - algorithmic challenge Bart <bc@freeuk.com> - 2026-04-01 23:33 +0100
        Re: Cookies in boxes - algorithmic challenge Richard Harnden <richard.nospam@gmail.invalid> - 2026-04-04 07:43 +0100
          Re: Cookies in boxes - algorithmic challenge Bart <bc@freeuk.com> - 2026-04-04 11:54 +0100
  Re: Cookies in boxes - algorithmic challenge DFS <nospam@dfs.com> - 2026-04-01 15:24 -0400
  Re: Cookies in boxes - algorithmic challenge DFS <nospam@dfs.com> - 2026-04-01 17:24 -0400
    Re: Cookies in boxes - algorithmic challenge Mike Terry <news.dead.person.stones@darjeeling.plus.com> - 2026-04-02 16:25 +0100
      Re: Cookies in boxes - algorithmic challenge Bart <bc@freeuk.com> - 2026-04-02 17:10 +0100
        Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-02 22:19 +0300
      Re: Cookies in boxes - algorithmic challenge DFS <nospam@dfs.com> - 2026-04-02 13:03 -0400
        Re: Cookies in boxes - algorithmic challenge Richard Harnden <richard.nospam@gmail.invalid> - 2026-04-02 18:52 +0100
        Re: Cookies in boxes - algorithmic challenge Bart <bc@freeuk.com> - 2026-04-02 19:50 +0100
          Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-02 22:24 +0300
        Re: Cookies in boxes - algorithmic challenge Mike Terry <news.dead.person.stones@darjeeling.plus.com> - 2026-04-02 20:13 +0100
          Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-02 22:36 +0300
      Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-02 22:14 +0300
    Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-02 22:10 +0300
      Re: Cookies in boxes - algorithmic challenge Tristan Wibberley <tristan.wibberley+netnews2@alumni.manchester.ac.uk> - 2026-04-06 22:36 +0100
        Re: Cookies in boxes - algorithmic challenge Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-04-06 15:42 -0700
        Re: Cookies in boxes - algorithmic challenge Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-04-06 15:44 -0700
  Re: Cookies in boxes - algorithmic challenge DFS <nospam@dfs.com> - 2026-04-04 13:33 -0400
    Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-04 21:03 +0300
      Re: Cookies in boxes - algorithmic challenge DFS <nospam@dfs.com> - 2026-04-04 14:19 -0400
      Re: Cookies in boxes - algorithmic challenge Bart <bc@freeuk.com> - 2026-04-04 20:22 +0100
        Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-04 22:40 +0300
  Re: Cookies in boxes - algorithmic challenge Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-04-04 17:08 -0700
  Re: Cookies in boxes - algorithmic challenge Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-04-08 08:42 -0700
    Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-08 22:23 +0300
      Re: Cookies in boxes - algorithmic challenge Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-04-09 21:22 -0700
        Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-10 12:23 +0300
          Re: Cookies in boxes - algorithmic challenge Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-04-10 22:41 -0700
        Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-10 16:16 +0300
          Re: Cookies in boxes - algorithmic challenge Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-04-11 04:27 -0700
        Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-11 22:56 +0300
          Re: Cookies in boxes - algorithmic challenge Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-04-11 15:57 -0700
            Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-12 02:15 +0300
            Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-13 02:03 +0300
            Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-13 17:11 +0300
              Re: Cookies in boxes - algorithmic challenge Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-04-16 23:52 -0700
                Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-17 14:44 +0300
                Re: Cookies in boxes - algorithmic challenge Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-04-17 07:40 -0700
                Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-17 18:30 +0300
                Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-20 00:43 +0300
                Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-21 20:37 +0300
                Re: Cookies in boxes - algorithmic challenge Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-04-21 18:22 -0700
                Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-22 12:05 +0300
    Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-15 02:15 +0300
      Re: Cookies in boxes - algorithmic challenge Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-04-16 02:57 -0700
        Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-17 17:04 +0300
  Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-08 23:45 +0300
    Re: Cookies in boxes - algorithmic challenge Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-04-09 16:37 -0700
      Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-10 17:02 +0300
        Re: Cookies in boxes - algorithmic challenge Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-04-11 03:45 -0700
  Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-09 00:01 +0300
    Re: Cookies in boxes - algorithmic challenge Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-04-09 17:07 -0700
      Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-10 18:06 +0300
        Re: Cookies in boxes - algorithmic challenge Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-04-11 04:31 -0700
        Re: Cookies in boxes - algorithmic challenge Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-04-16 03:22 -0700
  Re: Cookies in boxes - algorithmic challenge Bonita Montero <Bonita.Montero@gmail.com> - 2026-04-17 17:58 +0200
    Re: Cookies in boxes - algorithmic challenge Bonita Montero <Bonita.Montero@gmail.com> - 2026-04-17 18:08 +0200
    Re: Cookies in boxes - algorithmic challenge Bart <bc@freeuk.com> - 2026-04-17 17:47 +0100
      Re: Cookies in boxes - algorithmic challenge Bonita Montero <Bonita.Montero@gmail.com> - 2026-04-17 19:24 +0200
    Re: Cookies in boxes - algorithmic challenge scott@slp53.sl.home (Scott Lurndal) - 2026-04-17 19:58 +0000
      Re: Cookies in boxes - algorithmic challenge Bonita Montero <Bonita.Montero@gmail.com> - 2026-04-18 05:52 +0200
        Re: Cookies in boxes - algorithmic challenge Bart <bc@freeuk.com> - 2026-04-18 11:53 +0100
          Re: Cookies in boxes - algorithmic challenge Bart <bc@freeuk.com> - 2026-04-18 12:04 +0100
        Re: Cookies in boxes - algorithmic challenge Michael S <already5chosen@yahoo.com> - 2026-04-18 20:35 +0300
  Re: Cookies in boxes - algorithmic challenge Bonita Montero <Bonita.Montero@gmail.com> - 2026-04-17 19:52 +0200
    Re: Cookies in boxes - algorithmic challenge Bonita Montero <Bonita.Montero@gmail.com> - 2026-04-17 20:17 +0200

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