Re: (Golf) Kaprekar's Process

[MeowChow]

The answers given thus far all fail on numbers (such as 100 and 211) which generate two-digit numbers in their intermediate results. Here's a good test for this particular golf:

$| = 1;
for (100..999) {
  next if /(.)\1\1/;
  print "$_ : ", k($_), $/;
}

And here's a correct solution at 74 68 63 chars:

sub k {
  $_=sprintf"%03d",pop;/495/?0:1+k(-($_=join'',sort/./g)+reverse)
}

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

[Anonymous Monk]

sub k { 
  $_="000"|"@{[pop]}";/495/?0:1+k(-($_=join('',sort/./g)+reverse)
}

62

--sean

[MeowChow]

Verrrry cool idea... this can actually come down to 56:

sub k {
   $_="000"|"@_";/495/?0:1+k(-($_=join'',sort/./g)+reverse)
}

The interesting thing about this is that it's not the same as right-formatting the number via sprintf, since the 0 goes to the back, but it doesn't matter because the digits are reordered anyway.

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

[Anonymous Monk]

Yeah, i realized the whole @{[pop]} bit wasn't needed about 20 miles from home, figured someone would've already noticed it by the time i got back.. Here's one more:

sub k {
  $_=0 x3|"@_";/495/?0:1+k(-($_=join'',sort/./g)+reverse)
}

55

--sean