Beefy Boxes and Bandwidth Generously Provided by pair Networks
good chemistry is complicated,
and a little bit messy -LW
 
PerlMonks  

comment on

( [id://3333] : superdoc . print w/replies, xml ) Need Help??
We haven't had a golf in a while, so here it goes:

The problem is to write a perl golf (a solution in the fewest characters) to solve Kaprekar's Process. Kaprekar's Process basically states: "Take any number and arrange its digits in descending order and in ascending order and subtract. Repeat with the result. Ad Infinitum." Eventually, all 3 digit numbers (except when all digits are the same, like 333) will end up as 495. This is called Kaprekar's Constant. The program will return the number of steps it takes to get to 495.

Here is an example series:

Input: 213
1: 321 - 123 = 198
2: 981 - 189 = 792
3: 972 - 279 = 693
4: 963 - 369 = 594
5: 954 - 459 = 495

Input:

Your subrutine will recieve a 3 digit number; you may assume it is positive and that all the digits are not the same (i.e. you do not have to worry about error handling).

Output:

The return value will merely be the number of steps it took to reach 495; in the example above, it was 5. Here are a few sample calls: (assume sub name is a, it really doesn't matter what you name yours though)

print a(213) #prints 5
print a(258) #prints 2

Here is my attempt, weighing in at a bloated 60 chars:

sub a { return$i if$_[0]==495; $a=join'',sort{$a<=>$b}split//,pop; $i++; a((reverse$a)-$a) }

P.S. If it is still unclear to you, visit this website and look for Kaprekar's Process on it.

The 15 year old, freshman programmer,
Stephen Rawls


In reply to (Golf) Kaprekar's Process by srawls

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or How to display code and escape characters are good places to start.