From: Morton Goldberg <m_goldberg@...>
Date: 2007-06-19T06:02:52+09:00
Subject: Re: Another Easy Beginner Question

On Jun 18, 2007, at 1:19 PM, Matt Filizzi wrote:

> Wouldn't it be this...
>
> gifts = 0
> (1..12).each do |x|
>   (1..x).each do { |y| gifts += y }
                ^^
> end
> puts gifts

Not quite. It should be:

<code>
gifts = 0
(1..12).each do |x|
    (1..x).each { |y| gifts += y }
end
gifts # => 364
</code>

But this problem has a nice closed-form solution:

<code>
def gifts(days)
    days * (days +1) * (days + 2) / 6
end
gifts(12) # => 364
</code>

Regards, Morton