From: David Vincelli <micologist@...>
Date: 2005-10-23T10:14:16+09:00
Subject: combination sums of several arrays

I'm writing a little BlackJack program for fun and I'm at the point
where I have to decide which point value to assign to a hand. As you
know, an Ace may be worth 1 or 11 in this game - whatever is closer to
21 without going over.

Considering this, I know I have to come up with an algorithm that
first determines what the different point values may be (the extreme
case may be that a player got all four aces, now I'd have to determine
all combinations of the players cards).

This demonstrates some of the code I wrote:

pl = Player.new
pl.hand.each { |card|  p pl.card.value }

might produce this output:
[1, 11]
[5]
[10]

For the above example, so what I'm looking for is a method that will
calculate all possible point totals. For this example  I'd get the
results [16, 26]

I'm thinking I might do this by first building a binary tree, creating
unique branches that would add up to the results when I applied some
recursive algorithm to it. But I'm curious to know how other people
might do this? (I'm especially curious to see if anyone has some
solution that does not require building a tree and recursing..).

Thanks,

--
David Vincelli