Re: Google CodeJam?

From	vandys@vsta.org
Newsgroups	comp.lang.forth
Subject	Re: Google CodeJam?
Date	2012-04-27 16:37 +0000
Message-ID	<a000alF8vsU1@mid.individual.net> (permalink)
References	(7 earlier) <jn5obq01o0m@enews1.newsguy.com> <beaac66f-092f-4e0e-abe0-36c4b40656e1@f37g2000yqc.googlegroups.com> <jnb3u701rmd@enews4.newsguy.com> <9vtcdeFd1rU1@mid.individual.net> <7xmx5xttjj.fsf@ruckus.brouhaha.com>

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Paul Rubin <no.email@nospam.invalid> wrote:
> Maybe that could be written something like (untested):
>    from itertools import chain
>    def breadthfirst(tree, children=iter):
>       def t(fifo):
>          n1 = list(islice(fifo,1))
>          return chain(n1,fifo,children(n1) if n1 else [])
>       return t([tree])

No, even fixing errors (islice is also from itertools) it's not right.
I don't think itertools.chain is giving you the semantics you want.

> That's the more traditional way to do it.  It's prettier in Haskell, IMO:
> 
> data Tree a = Tree {value :: a, children :: [Tree a] }
> 
> breadthFirst t = bf1 [t] where
>  bf1 [] = []
>  bf1 (x:xs) = value x : bf1 (xs ++ children x)

My (uninformed--I don't know Haskell) reading sees this as a depth-first
traversal.  How does it achieve breadth-first semantics?

-- 
Andy Valencia
Home page: http://www.vsta.org/andy/
To contact me: http://www.vsta.org/contact/andy.html

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Re: Google CodeJam? hughaguilar96@yahoo.com - 2012-04-21 15:13 -0700
  Re: Google CodeJam? Bernd Paysan <bernd.paysan@gmx.de> - 2012-04-22 02:19 +0200
  Re: Google CodeJam? "WJ" <w_a_x_man@yahoo.com> - 2012-04-22 04:03 +0000
    Re: Google CodeJam? Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-04-22 23:08 -0700
    Re: Google CodeJam? Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-04-22 23:17 -0700
      Re: Google CodeJam? "WJ" <w_a_x_man@yahoo.com> - 2012-04-23 19:27 +0000
        Re: Google CodeJam? Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-04-23 22:08 -0700
          Re: Google CodeJam? "WJ" <w_a_x_man@yahoo.com> - 2012-04-24 08:30 +0000
            Re: Google CodeJam? Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-04-24 23:00 -0700
              Re: Google CodeJam? "WJ" <w_a_x_man@yahoo.com> - 2012-04-26 09:19 +0000
                Re: Google CodeJam? Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-04-26 03:17 -0700
                Re: Google CodeJam? vandys@vsta.org - 2012-04-26 16:45 +0000
                Re: Google CodeJam? Paul Rubin <no.email@nospam.invalid> - 2012-04-26 10:47 -0700
                Re: Google CodeJam? Paul Rubin <no.email@nospam.invalid> - 2012-04-27 02:26 -0700
                Re: Google CodeJam? vandys@vsta.org - 2012-04-27 16:37 +0000
                Re: Google CodeJam? Paul Rubin <no.email@nospam.invalid> - 2012-04-27 10:17 -0700
                Re: Google CodeJam? vandys@vsta.org - 2012-04-27 18:15 +0000
        Re: Google CodeJam? Rugxulo <rugxulo@gmail.com> - 2012-04-26 16:00 -0700
  Re: Google CodeJam? awegel@arcor.de (Alex Wegel) - 2012-04-22 12:12 +0200
    Re: Google CodeJam? awegel@arcor.de (Alex Wegel) - 2012-04-22 14:11 +0200
      Re: Google CodeJam? awegel@arcor.de (Alex Wegel) - 2012-04-22 14:17 +0200
        Re: Google CodeJam? awegel@arcor.de (Alex Wegel) - 2012-04-25 14:25 +0200
    Re: Google CodeJam? mhx@iae.nl (Marcel Hendrix) - 2012-04-22 18:23 +0200
      Re: Google CodeJam? awegel@arcor.de (Alex Wegel) - 2012-04-22 22:24 +0200
        Re: Google CodeJam? mhx@iae.nl (Marcel Hendrix) - 2012-04-23 20:59 +0200
          Re: Google CodeJam? Paul Rubin <no.email@nospam.invalid> - 2012-04-23 13:56 -0700
    Re: Google CodeJam? mhx@iae.nl (Marcel Hendrix) - 2012-04-22 18:29 +0200
      Re: Google CodeJam? awegel@arcor.de (Alex Wegel) - 2012-04-22 21:36 +0200
    Re: Google CodeJam? Bernd Paysan <bernd.paysan@gmx.de> - 2012-04-22 23:08 +0200
      Re: Google CodeJam? Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-04-22 23:06 -0700
      Re: Google CodeJam? awegel@arcor.de (Alex Wegel) - 2012-04-23 23:19 +0200
        Re: Google CodeJam? Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-04-23 22:35 -0700
          Re: Google CodeJam? awegel@arcor.de (Alex Wegel) - 2012-04-25 01:59 +0200
            Re: Google CodeJam? Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-04-24 22:16 -0700
              Re: Google CodeJam? awegel@arcor.de (Alex Wegel) - 2012-04-25 14:25 +0200
                Re: Google CodeJam? Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-04-25 11:58 -0700
                Re: Google CodeJam? awegel@arcor.de (Alex Wegel) - 2012-04-26 00:23 +0200
                Re: Google CodeJam? Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-04-25 11:58 -0700
                Re: Google CodeJam? awegel@arcor.de (Alex Wegel) - 2012-04-26 00:23 +0200
                Re: Google CodeJam? Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-04-25 11:58 -0700
                Re: Google CodeJam? awegel@arcor.de (Alex Wegel) - 2012-04-26 00:23 +0200
                Re: Google CodeJam? Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-04-26 12:36 +0000
              Re: Google CodeJam? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-04-25 13:39 +0000
                Re: Google CodeJam? Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-04-25 10:05 -0700
                Re: Google CodeJam? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-04-26 16:30 +0000
              Re: Google CodeJam? Bernd Paysan <bernd.paysan@gmx.de> - 2012-04-27 15:21 +0200
        Re: Google CodeJam? Paul Rubin <no.email@nospam.invalid> - 2012-04-24 00:51 -0700
          Re: Google CodeJam? awegel@arcor.de (Alex Wegel) - 2012-04-25 01:59 +0200
    Re: Google CodeJam? awegel@arcor.de (Alex Wegel) - 2012-04-25 01:59 +0200
      Re: Google CodeJam? awegel@arcor.de (Alex Wegel) - 2012-04-27 14:15 +0200
        Re: Google CodeJam? hughaguilar96@yahoo.com - 2012-04-30 23:54 -0700
          Re: Google CodeJam? awegel@arcor.de (Alex Wegel) - 2012-05-02 01:44 +0200
            Re: Google CodeJam? Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-05-01 20:45 -0700
              Re: Google CodeJam? awegel@arcor.de (Alex Wegel) - 2012-05-02 23:38 +0200
  Re: Google CodeJam? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2012-04-24 12:50 +0100
    Re: Google CodeJam? Paul Rubin <no.email@nospam.invalid> - 2012-04-24 08:22 -0700
    Re: Google CodeJam? mhx@iae.nl (Marcel Hendrix) - 2012-04-24 22:28 +0200
      Re: Google CodeJam? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2012-04-25 09:50 +0100
    Re: Google CodeJam? awegel@arcor.de (Alex Wegel) - 2012-04-25 01:59 +0200
      Re: Google CodeJam? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2012-04-25 09:49 +0100

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