Re: (Golf) Kaprekar's Process

[srawls]

I've taken all the advice and improved my old one to this, 61 char solution (I counted manually this time : ). Oh, and it handles 0s in numbers correctly (well, I don't know if it's correct, but it doesn't freeze up like before). Here it is:

sub a {
$_=pop;/495/&&$i||do{$_=join'',sort/./g;$i++;a(reverse()-$_)}
#234567890123456789012345678901234567890123456789012345678901
}

Update:Changed code from 65 chars to 61.

The 15 year old, freshman programmer,
Stephen Rawls

[MeowChow]

... it handles 0s in numbers correctly

a(100)

There are many such cases, though I misstated the problem somewhat. It isn't so much zeroed digits, as intermediate two-digit results. So far, all the solutions in this thread (except my own :) fail on many three-digit numbers.

Also, in Golf, it may be ok to violate strict, but your subroutine should be re-runnable (ie. $i should be reset somewhere).

   MeowChow                                   
               s aamecha.s a..a\u$&owag.print

[srawls]

Oh, I see: 100 - 001 is 99; 99 - 99 is zero. Now we've got an infinite loop. Just out of curiosity, how would you solve that? Your solution gives 6 (which is most likely right), I just don't see how.

The 15 year old, freshman programmer,
Stephen Rawls

[MeowChow]

That's what the sprintf is there for. It formats a two-digit result into a three-digit string, eg. 099. After sorting and reversal, you get 990 - 099.

   MeowChow                                   
               s aamecha.s a..a\u$&owag.print