http://qs1969.pair.com?node_id=89179


in reply to Re: (Golf) Kaprekar's Process
in thread (Golf) Kaprekar's Process

This doesn't work for a lot of numbers, because you're checking AFTER the sort, for 459, which could've been 459,495,954,945,549, or 594 before the sort. your code gets the right answer when it was anything EXCEPT 495 before the sort.
For example, 247:

1: 742-247 = 495
the answer is 1.

your code produces 2.

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Re: Re: Re: (Golf) Kaprekar's Process
by tachyon (Chancellor) on Jun 18, 2001 at 03:19 UTC

    Good point, what can I say, seemed like a good idea at the time. The thinking was that any combination of 4,5,9 will sort to 954 and reverse to 459 so the timing of the sort was not important. As you note this breaks down in some cases. The QA was a bit suboptimal - I just bunged in the two examples and when they worked...

    Drat! I knew sneaking in a solution shorter than MeowChow was to good to be true :-)

    Cheers

    tachyon