Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.javascript > #25251

Re: Bijective basechanger

Show all headers | View raw

Den lördagen den 5:e juli 2014 kl. 21:12:57 UTC+2 skrev Scott Sauyet:
> jonas.thornvall@gmail.com wrote: 
> 
> > skrev Scott Sauyet:
> 
> >> Here is my approach:
> 
> >> 
> 
> >>    var zeroless = function(nbr, base) {
> 
> >>      if (!nbr || nbr === 0) {return "";}
> 
> >>      if (!base) {base = 10;}
> 
> >>      var str = "" + nbr.toString(base); 
> 
> >>      var lastChar = str.slice(-1); 
> 
> >>      var beginning = str.slice(0, -1); 
> 
> >>      return lastChar === "0" ? 
> 
> >>        zeroless(parseInt(beginning, base) - 1, base) + 
> 
> >>               (base).toString(base + 1).toUpperCase() : 
> 
> >>        zeroless(parseInt(beginning, base), base) + lastChar;
> 
> >>    };
> 
> > 
> 
> > It works Scott, i checked binary and ternary 
> 
> 
> 
> I'm glad it works.  But this really wasn't a big leap from
> 
> the earlier version I posted that worked only in base 10.
> 
> 
> 
> > i must say every time i look at recursive function calls 
> 
> > it is really hard for me to follow the code, but i probably 
> 
> > should learn howto code it. 
> 
> 
> 
> Recursion should generally be IMHO *easier* to understand.
> 
> It's the process of breaking your problem down into smaller
> 
> sub-problems and solving those.
> 
> 
> 
> This solution works (in base 10) by splitting the digits in
> 
> two parts: the final digit and the set up to the final digit.
> 
> If the final digit is not zero 0, then we're in the easy case,
> 
> and all we do is process the remaining digits and append that
> 
> final digit to that result.  If that final digit is a 0, then 
> 
> we have to think of it as a 10, which means we have to subtract
> 
> one from the remaining digits before processing them and
> 
> appending the "A" for 10.  The only thing left is to work out
> 
> the base of the recursion, which turns out to be pretty easy,
> 
> because we can just check if the number is zero.
> 
> 
> 
> > I will try figure out why my while loop approach fail.
> 
> 
> 
> That's probably a good idea. 
> 
> 
> 
> 
> 
> > Thanks again Scott
> 
> 
> 
> You're welcome.  You could express your gratitude well by 
> 
> learning to quote appropriately on USENET.  Your posts are
> 
> very hard to read.
> 
> 
> 
> One final question.  Is this actually useful for something?
> 
> Or is it mostly a puzzle?
> 
> 
> 
>   -- Scott

Actually it is necessary to be able to factor big primeproducts in none exponential time. I think it was around 4 hours on a 486DX around 1998. Of course the number system itself is not the solution on howto factor large primeproducts, but it is part of the approach how to do it.

Back to comp.lang.javascript | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Bijective basechanger jonas.thornvall@gmail.com - 2014-06-17 06:42 -0700
  Re: Bijective basechanger "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2014-06-17 12:08 -0700
    Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-17 13:23 -0700
      Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-17 13:24 -0700
      Re: Bijective basechanger "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2014-06-17 13:54 -0700
        Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-17 14:07 -0700
          Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-17 14:15 -0700
            Re: Bijective basechanger John Harris <niam@jghnorth.org.uk.invalid> - 2014-06-23 17:23 +0100
        Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-17 14:23 -0700
        Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-17 14:41 -0700
          Re: Bijective basechanger "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2014-06-17 20:28 -0700
            Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-18 13:04 -0700
              Re: Bijective basechanger "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2014-06-18 16:30 -0700
                Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-18 17:45 -0700
                Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-18 17:49 -0700
                Re: Bijective basechanger "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2014-06-19 11:21 -0700
                Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-19 14:44 -0700
                Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-19 14:48 -0700
                Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-19 14:55 -0700
                Re: Bijective basechanger "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2014-06-19 19:59 -0700
                Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-21 09:25 -0700
                Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-21 11:15 -0700
                Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-18 18:05 -0700
                Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-18 18:19 -0700
                Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-18 18:25 -0700
                Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-18 18:46 -0700
            Re: Bijective basechanger "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2014-06-23 16:00 -0700
              Re: Bijective basechanger "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2014-06-23 17:51 -0700
  Re: Bijective basechanger John Harris <niam@jghnorth.org.uk.invalid> - 2014-06-23 17:18 +0100
    Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-23 11:27 -0700
  Re: Bijective basechanger Scott Sauyet <scott.sauyet@gmail.com> - 2014-06-23 15:29 -0700
    Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-24 03:26 -0700
      Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-24 03:28 -0700
      Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-24 04:24 -0700
        Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-24 05:36 -0700
        Re: Bijective basechanger Scott Sauyet <scott.sauyet@gmail.com> - 2014-06-24 13:05 -0700
          Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-24 14:13 -0700
            Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-25 05:36 -0700
            Re: Bijective basechanger Scott Sauyet <scott.sauyet@gmail.com> - 2014-06-25 12:45 -0700
              Re: Bijective basechanger Scott Sauyet <scott.sauyet@gmail.com> - 2014-06-25 13:15 -0700
                Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-07-01 02:39 -0700
                Re: Bijective basechanger Scott Sauyet <scott.sauyet@gmail.com> - 2014-07-03 07:33 -0700
                Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-07-03 09:54 -0700
                Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-07-04 02:14 -0700
                Re: Bijective basechanger Scott Sauyet <scott.sauyet@gmail.com> - 2014-07-05 12:12 -0700
                Re: Bijective basechanger "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-07-05 22:19 +0200
                Re: Bijective basechanger Scott Sauyet <scott.sauyet@gmail.com> - 2014-07-05 13:50 -0700
                Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-07-06 11:11 -0700
                Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-07-06 14:59 -0700
                Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-07-06 15:00 -0700
                Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-07-06 15:02 -0700
                Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-07-16 23:31 -0700
                Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-07-04 02:28 -0700
                Re: Bijective basechanger Scott Sauyet <scott.sauyet@gmail.com> - 2014-07-05 12:14 -0700
          Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-25 22:38 -0700
    Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-24 03:32 -0700
    Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-24 03:44 -0700
    Re: Bijective basechanger jonas.thornvall@gmail.com - 2014-06-24 11:10 -0700
      Re: Bijective basechanger Scott Sauyet <scott.sauyet@gmail.com> - 2014-06-24 11:45 -0700
  Re: Bijective basechanger "Chris M. Thomasson" <no@spam.invalid> - 2014-07-22 12:16 -0700

csiph-web