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Re: Python 3.3 vs. MSDOS Basic

References <e8a634af-4e29-4f45-b327-2dfd1fab5269@googlegroups.com> <mailman.1973.1361224508.2939.python-list@python.org> <orfcv9-do51.ln1@ozzie.tundraware.com>
From Ian Kelly <ian.g.kelly@gmail.com>
Date 2013-02-19 11:31 -0700
Subject Re: Python 3.3 vs. MSDOS Basic
Newsgroups comp.lang.python
Message-ID <mailman.2057.1361298729.2939.python-list@python.org> (permalink)

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On Tue, Feb 19, 2013 at 7:46 AM, Tim Daneliuk <tundra@tundraware.com> wrote:
> Are you sure you wouldn't like to share with the class?  I'd be interested
> in seeing your approach...

Very well:

def collatz(n, memo):
    if n not in memo:
        if n % 2 == 0:
            next_n = n // 2
        else:
            next_n = 3 * n + 1
        memo[n] = collatz(next_n, memo) + 1
    return memo[n]

def run_collatz(upper):
    table = {1: 0}
    max_n = max(range(1, upper), key=lambda n: collatz(n, table))
    return max_n, table[max_n]

>>> run_collatz(1000000)
(837799, 524)

It could certainly be optimized further, but at about 4 seconds it's
already fast enough for most purposes.

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Thread

Python 3.3 vs. MSDOS Basic John Immarino <johimm@gmail.com> - 2013-02-18 11:13 -0800
  Re: Python 3.3 vs. MSDOS Basic Chris Angelico <rosuav@gmail.com> - 2013-02-19 08:55 +1100
  Re: Python 3.3 vs. MSDOS Basic Ian Kelly <ian.g.kelly@gmail.com> - 2013-02-18 14:54 -0700
    Re: Python 3.3 vs. MSDOS Basic Tim Daneliuk <tundra@tundraware.com> - 2013-02-19 08:46 -0600
      Re: Python 3.3 vs. MSDOS Basic Ian Kelly <ian.g.kelly@gmail.com> - 2013-02-19 11:31 -0700
        Re: Python 3.3 vs. MSDOS Basic Tim Daneliuk <tundra@tundraware.com> - 2013-02-20 08:21 -0600
          Re: Python 3.3 vs. MSDOS Basic Ian Kelly <ian.g.kelly@gmail.com> - 2013-02-20 11:38 -0700
            Re: Python 3.3 vs. MSDOS Basic Tim Daneliuk <tundra@tundraware.com> - 2013-02-20 16:49 -0600
              Re: Python 3.3 vs. MSDOS Basic Tim Daneliuk <tundra@tundraware.com> - 2013-02-20 16:59 -0600
      Re: Python 3.3 vs. MSDOS Basic Serhiy Storchaka <storchaka@gmail.com> - 2013-02-19 22:28 +0200
      Re: Python 3.3 vs. MSDOS Basic Chris Angelico <rosuav@gmail.com> - 2013-02-20 08:39 +1100
        Re: Python 3.3 vs. MSDOS Basic Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2013-02-20 18:32 +1300
  Re: Python 3.3 vs. MSDOS Basic Chris Angelico <rosuav@gmail.com> - 2013-02-19 08:56 +1100
  Re: Python 3.3 vs. MSDOS Basic Chris Angelico <rosuav@gmail.com> - 2013-02-19 08:58 +1100
    Re: Python 3.3 vs. MSDOS Basic John Immarino <johimm@gmail.com> - 2013-02-18 17:39 -0800
      Re: Python 3.3 vs. MSDOS Basic Chris Angelico <rosuav@gmail.com> - 2013-02-19 14:01 +1100
        Re: Python 3.3 vs. MSDOS Basic Nick Mellor <thebalancepro@gmail.com> - 2013-02-18 20:17 -0800
        Re: Python 3.3 vs. MSDOS Basic Nick Mellor <thebalancepro@gmail.com> - 2013-02-18 20:17 -0800
    Re: Python 3.3 vs. MSDOS Basic John Immarino <johimm@gmail.com> - 2013-02-18 17:39 -0800
      Re: Python 3.3 vs. MSDOS Basic Neil Cerutti <neilc@norwich.edu> - 2013-02-20 17:06 +0000
  Re: Python 3.3 vs. MSDOS Basic Chris Angelico <rosuav@gmail.com> - 2013-02-19 09:01 +1100
  Re: Python 3.3 vs. MSDOS Basic Ian Kelly <ian.g.kelly@gmail.com> - 2013-02-18 15:15 -0700
  Re: Python 3.3 vs. MSDOS Basic Alexander Blinne <news@blinne.net> - 2013-02-19 01:11 +0100
  Re: Python 3.3 vs. MSDOS Basic Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-02-18 19:36 -0500
    Re: Python 3.3 vs. MSDOS Basic John Immarino <johimm@gmail.com> - 2013-02-18 17:47 -0800
    Re: Python 3.3 vs. MSDOS Basic John Immarino <johimm@gmail.com> - 2013-02-18 17:47 -0800
  Re: Python 3.3 vs. MSDOS Basic Terry Reedy <tjreedy@udel.edu> - 2013-02-18 19:50 -0500
    Re: Python 3.3 vs. MSDOS Basic Piet van Oostrum <piet@vanoostrum.org> - 2013-02-19 12:42 +0100
      Re: Python 3.3 vs. MSDOS Basic Alexander Blinne <news@blinne.net> - 2013-02-20 01:23 +0100
        Re: Python 3.3 vs. MSDOS Basic Ian Kelly <ian.g.kelly@gmail.com> - 2013-02-19 18:04 -0700
  Re: Python 3.3 vs. MSDOS Basic Terry Reedy <tjreedy@udel.edu> - 2013-02-19 00:28 -0500
  Re: Python 3.3 vs. MSDOS Basic Anssi Saari <as@sci.fi> - 2013-02-19 12:52 +0200
  Re: Python 3.3 vs. MSDOS Basic Serhiy Storchaka <storchaka@gmail.com> - 2013-02-19 13:13 +0200
  Re: Python 3.3 vs. MSDOS Basic Olive <diolu.remove_this_part@bigfoot.com> - 2013-02-19 15:02 +0100

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