On Fri, 02 May 2008 10:28:00 -0500, Matthew Moss wrote:
> Quiz #161
> Reverse Divisible Numbers
> 
> This week's quiz is borrowed from Jon Galloway (http://tinyurl.com/
> 5jvf37).
> Don't read the comments or solution there without trying this first!
> 
> Your task is to write a bit of Ruby code that will find and report all
> integers that are divisible by their reverse. For example, 9801 is
> divisible by 1089.
> 
> Your script should accept a single, optional argument to specify the
> upper
> limit of your search. If not provided, the default should be one
> million.
> 
> There are two extra rules for finding these "reverse divisible" numbers:
> 
> 1. Don't count palindromes; they are obviously reverse-divisible. 2.
> Don't count numbers ending with zero. Reversing such numbers forces you
>    to drop leading zeros on the divisor, and that's not as much fun.

Here's what I've found:

1089 * 9 = 9801
2178 * 4 = 8712
10989 * 9 = 98901
21978 * 4 = 87912
109989 * 9 = 989901
219978 * 4 = 879912

real	0m55.234s
user	0m53.995s
sys	0m0.012s

--Ken

-- 
Ken (Chanoch) Bloom. PhD candidate. Linguistic Cognition Laboratory.
Department of Computer Science. Illinois Institute of Technology.
http://www.iit.edu/~kbloom1/