From: Gavin Kistner <gavin@...>
Date: 2004-10-03T23:35:11+09:00
Subject: Re: [SOLUTION] Secret Santas (#2)

My solution to the Quiz #2 is at http://phrogz.net/RubyLibs/quiz/2/

The general approach is:
a) Create a randomized array of Person objects (having parsed the 
input).
b) Turn the array into a circular list, and separate any adjacent 
family members.
c) Send email (or, if $DEBUG is set, spit out a message), treating 
adjacent pairs in the list as giver/receivers.

I initially wrote it treating the array as a circular list, but then 
decided I wanted a real circular list class. It's not well tested yet, 
but if you like, the Ouroboros class I created is free for the horking. 
(It's in the above url, as well as documented and available in main 
http:/phrogz.net/RubyLibs/)

I thought I had a better, less-hackish solution than the 
pseduo-bubble-sort method I used to separate adjacent duplicates. I 
sorted people into family bins, randomized the families, and then 
pulled people out from one bin at a time. The benefit was supposed to 
be better family separation (to limit occurrances of John Doe from 
giving to Bob Smith who gave right back to Jane Doe). Unfortunately, I 
didn't think of the case of a single many-member family overpowering 
the pool, where early even distribution ends up with only members from 
that family left at the end.

I was thinking about weighting my choices by the number of people in 
each bin, but since the above solution works, I decided to scrap it.


The interesting thing about this quiz is...my extended family does the 
same thing, and up until now no one had thought to automate the 
no-same-family rule. The list of members was randomized in excel (much 
like Ruby: sort names by an adjacent random number column) and then the 
list manually massaged to ensure no family members were adjacent.

I'd never worked with STDIN or SMTP before, so this was a great 
exercise for me. Looking forward to looking through other's solutions. 
Thanks again for a fun quiz!
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