Re: Euler 13

From	Paul Rubin <no.email@nospam.invalid>
Newsgroups	comp.lang.forth
Subject	Re: Euler 13
Date	2013-05-26 15:40 -0700
Organization	Nightsong/Fort GNOX
Message-ID	<7x4ndpbc04.fsf@ruckus.brouhaha.com> (permalink)
References	(2 earlier) <a_OdnUy-Qa0EJjzMnZ2dnUVZ_o6dnZ2d@supernews.com> <7x1u8u185g.fsf@ruckus.brouhaha.com> <y7OdndMSTMqpbjzMnZ2dnUVZ_q-dnZ2d@supernews.com> <7xfvx9y89i.fsf@ruckus.brouhaha.com> <11ab37b2-fcd4-47ee-9f4d-95e6df20ada0@googlegroups.com>

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visualforth@rocketmail.com writes:
> I solved the problem in the first place using my little knowledge
> about Forth, doing the same arithmetic which I had learned in primary
> school. That's why I did know from the beginning that the result will
> be okay.

With Euler 13 and maybe the other low numbered problems, that approach
works.  Euler problems mostly aren't programming exercises though.  They
are math problems whose solutions involve enough calculating that you
need a computer, usually with a clever algorithm based on a math trick.
So the challenge is finding the math trick rather than writing the
program.  They typically also have an obvious brute force solution that
is too slow for the allocated 1 minute of computer time.  The idea is to
avoid the brute force solution and look for something better.

That's why I liked Marcel's answer, even though the brute force solution
for problem 13 is also very fast.

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comp.lang.forth.applications johno <email@address.com> - 2013-05-23 15:35 +0100
  Re: comp.lang.forth.applications albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-05-23 15:38 +0000
    Re: comp.lang.forth.applications "Elizabeth D. Rather" <erather@forth.com> - 2013-05-23 08:25 -1000
      Re: comp.lang.forth.applications Mentifex <mentifex@myuw.net> - 2013-05-23 11:43 -0700
    Re: comp.lang.forth.applications visualforth@rocketmail.com - 2013-05-23 18:35 -0700
      Re: comp.lang.forth.applications Paul Rubin <no.email@nospam.invalid> - 2013-05-23 22:38 -0700
        Re: comp.lang.forth.applications albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-05-24 08:52 +0000
          Re: comp.lang.forth.applications visualforth@rocketmail.com - 2013-05-25 17:52 -0700
            Re: comp.lang.forth.applications Paul Rubin <no.email@nospam.invalid> - 2013-05-25 18:18 -0700
        Re: comp.lang.forth.applications Doug Hoffman <glidedog@gmail.com> - 2013-05-24 05:24 -0400
          Re: comp.lang.forth.applications visualforth@rocketmail.com - 2013-05-25 18:12 -0700
        Re: comp.lang.forth.applications "WJ" <w_a_x_man@yahoo.com> - 2013-06-08 11:46 +0000
          Re: comp.lang.forth.applications Doug Hoffman <glidedog@gmail.com> - 2013-06-08 08:55 -0400
        Re: comp.lang.forth.applications "WJ" <w_a_x_man@yahoo.com> - 2013-06-09 19:21 +0000
      Re: comp.lang.forth.applications m.a.m.hendrix@tue.nl - 2013-05-23 23:55 -0700
        Re: comp.lang.forth.applications visualforth@rocketmail.com - 2013-05-25 17:40 -0700
          Re: comp.lang.forth.applications mhx@iae.nl (Marcel Hendrix) - 2013-05-26 09:18 +0200
            Re: comp.lang.forth.applications Paul Rubin <no.email@nospam.invalid> - 2013-05-26 00:24 -0700
            Euler 13 [Was: comp.lang.forth.applications] Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-05-26 02:36 -0500
              Re: Euler 13 Paul Rubin <no.email@nospam.invalid> - 2013-05-26 01:02 -0700
                Re: Euler 13 Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-05-26 06:34 -0500
                Re: Euler 13 Paul Rubin <no.email@nospam.invalid> - 2013-05-26 10:13 -0700
                Re: Euler 13 visualforth@rocketmail.com - 2013-05-26 15:32 -0700
                Re: Euler 13 Paul Rubin <no.email@nospam.invalid> - 2013-05-26 15:40 -0700
              Euler 13 [Was: comp.lang.forth.applications] mhx@iae.nl (Marcel Hendrix) - 2013-05-26 11:06 +0200
                Re: Euler 13 [Was: comp.lang.forth.applications] mhx@iae.nl - 2013-05-26 02:28 -0700
                Re: Euler 13 [Was: comp.lang.forth.applications] "David N. Williams" <williams@umich.edu> - 2013-05-26 10:19 -0400
                Re: Euler 13 [Was: comp.lang.forth.applications] visualforth@rocketmail.com - 2013-05-26 15:24 -0700
                Re: Euler 13 [Was: comp.lang.forth.applications] Coos Haak <chforth@hccnet.nl> - 2013-05-27 01:11 +0200
                Re: Euler 13 [Was: comp.lang.forth.applications] visualforth@rocketmail.com - 2013-05-26 22:36 -0700
                Re: Euler 13 [Was: comp.lang.forth.applications] Alex McDonald <blog@rivadpm.com> - 2013-05-27 01:49 -0700
                Re: Euler 13 [Was: comp.lang.forth.applications] anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-05-27 08:56 +0000
                Re: Euler 13 [Was: comp.lang.forth.applications] "David N. Williams" <williams@umich.edu> - 2013-05-27 08:04 -0400
                Re: Euler 13 [Was: comp.lang.forth.applications] humptydumpty <ouatubi@gmail.com> - 2013-05-27 12:55 -0700
              Re: Euler 13 [Was: comp.lang.forth.applications] albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-05-26 17:24 +0000
                Re: Euler 13 [Was: comp.lang.forth.applications] albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-05-26 17:26 +0000
                Re: Euler 13 Paul Rubin <no.email@nospam.invalid> - 2013-05-26 21:25 -0700
                Re: Euler 13 albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-05-27 12:13 +0000
                Re: Euler 13 Paul Rubin <no.email@nospam.invalid> - 2013-05-27 07:44 -0700
            Re: comp.lang.forth.applications Paul Rubin <no.email@nospam.invalid> - 2013-05-26 01:04 -0700
            Re: comp.lang.forth.applications visualforth@rocketmail.com - 2013-05-26 15:05 -0700
              Re: comp.lang.forth.applications mhx@iae.nl (Marcel Hendrix) - 2013-05-27 01:12 +0200
                Re: comp.lang.forth.applications visualforth@rocketmail.com - 2013-05-26 22:32 -0700
  Re: comp.lang.forth.applications "Ed" <invalid@invalid.com> - 2013-05-24 12:00 +1000
    Re: comp.lang.forth.applications stephenXXX@mpeforth.com (Stephen Pelc) - 2013-05-24 10:16 +0000
      Re: comp.lang.forth.applications "Ed" <invalid@invalid.com> - 2013-05-24 20:44 +1000
        Re: comp.lang.forth.applications Doug Hoffman <glidedog@gmail.com> - 2013-05-24 07:03 -0400
          Re: comp.lang.forth.applications "Ed" <invalid@invalid.com> - 2013-05-27 22:00 +1000
            Re: comp.lang.forth.applications "Elizabeth D. Rather" <erather@forth.com> - 2013-05-27 08:08 -1000
              Re: comp.lang.forth.applications "Ed" <invalid@invalid.com> - 2013-05-29 13:56 +1000
                Re: comp.lang.forth.applications albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-05-29 04:05 +0000
                Re: comp.lang.forth.applications rickman <gnuarm@gmail.com> - 2013-05-29 16:25 -0400
                Re: comp.lang.forth.applications albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-05-30 00:31 +0000
            Re: comp.lang.forth.applications "Paul E. Bennett" <Paul_E.Bennett@topmail.co.uk> - 2013-05-27 23:34 +0100
              Re: comp.lang.forth.applications "Ed" <invalid@invalid.com> - 2013-05-29 13:51 +1000
                Re: comp.lang.forth.applications Alex McDonald <blog@rivadpm.com> - 2013-05-29 00:14 -0700
                Re: comp.lang.forth.applications Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-05-29 04:01 -0500
                Re: comp.lang.forth.applications rickman <gnuarm@gmail.com> - 2013-05-29 16:35 -0400
                Re: comp.lang.forth.applications rickman <gnuarm@gmail.com> - 2013-06-08 22:16 -0400
                Re: comp.lang.forth.applications Brad Eckert <hwfwguy@gmail.com> - 2013-06-10 14:17 -0700
                Re: comp.lang.forth.applications rickman <gnuarm@gmail.com> - 2013-06-10 19:06 -0400
        Re: comp.lang.forth.applications stephenXXX@mpeforth.com (Stephen Pelc) - 2013-05-24 12:30 +0000
          Re: comp.lang.forth.applications the_gavino_himself <visphatesjava@gmail.com> - 2013-05-24 23:14 -0700
          Re: comp.lang.forth.applications rickman <gnuarm@gmail.com> - 2013-05-26 22:18 -0400
      Re: comp.lang.forth.applications Paul Rubin <no.email@nospam.invalid> - 2013-05-24 07:57 -0700
        Re: comp.lang.forth.applications Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-05-24 10:33 -0500
        Re: comp.lang.forth.applications stephenXXX@mpeforth.com (Stephen Pelc) - 2013-05-24 16:34 +0000
          Re: comp.lang.forth.applications Paul Rubin <no.email@nospam.invalid> - 2013-05-24 10:23 -0700
      Re: comp.lang.forth.applications "Paul E. Bennett" <Paul_E.Bennett@topmail.co.uk> - 2013-05-24 20:00 +0100
        Re: comp.lang.forth.applications "Elizabeth D. Rather" <erather@forth.com> - 2013-05-24 09:32 -1000
          Re: comp.lang.forth.applications Paul Rubin <no.email@nospam.invalid> - 2013-05-24 20:18 -0700
            Re: comp.lang.forth.applications "Elizabeth D. Rather" <erather@forth.com> - 2013-05-24 19:31 -1000
  Re: comp.lang.forth.applications oh2aun@gmail.com - 2013-05-23 20:56 -0700
  Re: comp.lang.forth.applications the_gavino_himself <visphatesjava@gmail.com> - 2013-05-24 23:02 -0700
  Re: comp.lang.forth.applications rickman <gnuarm@gmail.com> - 2013-06-08 19:21 -0400

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