From: Gavin Kistner <gavin@...>
Date: 2004-10-04T21:59:00+09:00
Subject: Re: [SOLUTION] Secret Santas (#2)

On Oct 4, 2004, at 2:43 AM, Peter wrote:
> The way you look at it, each person in your arrangement is the next
> person's secret Santa, wrapping around the end of the array as needed,
> right? Actually that's like putting people in a circle such that each
> person's secret Santa is standing to his/her left (or right).

Correct. (Indeed, I wrote my own circular list class because that's 
exactly how I was looking at it :)

> But actually that leaves out the arrangements with multiple smaller 
> circles, so you
> can't generate every solution this way.

Good point...I hadn't considered that!
Is it a good or bad thing that these smaller circles might be two 
reciprocating people?
I suppose it adds to the surprise if/when it occurs.


>  But James' solution does however.

Apparently my RRC (Ruby Reading Comprehension) is not good. I 
misunderstood Jame's solution at first. I didn't realize it was a 1<->1 
mapping in to lists. (I failed to see that there were both $players and 
$santas being compared in his #check_families? method.)

I like the smaller-circles possibility, and if speed were a problem, 
you could add people to $santas in a more deterministic fashion 
(randomize a copy, and then find the first available slot for the 
person) rather easily.


The multiplicity of solutions here is pretty sweet. :)
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