From: "Jesús Gabriel y Galán" <jgabrielygalan@...>
Date: 2007-11-23T01:48:35+09:00
Subject: Re: How to give depth to arrays?

On Nov 22, 2007 3:03 PM, Jesús Gabriel y Galán <jgabrielygalan@gmail.com> wrote:
> On Nov 22, 2007 10:28 AM, Chris Morales <primo.tertio@gmail.com> wrote:
> > p [2,3,3,5,4,4].depthen => [2,[3,3,[[5],4,4]]]
> >
> > I will be really thankful if anybody could help me improve this monster
> > with nice ruby tricks.
>
>
> With your code:
>
> [2,3,5,3].depthen # => [2, [3, [[5], 3]]]
>
> Shouldn't this be:
>
> [2, [3, [[5]], 3]]
>
> ?
>
> I'm trying to think of an elegant solution, but I'm kind of slow today...

I managed to get some time at work and this is my first try,
I use a stack to maintain the arrays for each level when you are
going upwards, so you can add to the same array when you go
downwards (makes any sense?):

class Array
        def depthen
                depth = self[0]
                result = []
                stack = []
                current = result
                each do |x|
                case depth <=> x
                when 0
                        current << x
                when -1
                        diff = x - depth
                        value = [x]
                        tmp = value
                        (diff - 1).times do
                                value = [value]
                                stack.push value
                        end
                        current << value
                        current = tmp
                        stack.push current
                when 1
                        diff = depth - x + 1
                        diff.times {current = stack.pop}
                        current = result if current.nil?
                        current << x
                end
                depth = x
                end
                result
        end
end


a = [[2,3,3,4,5,4,4], [2,3,5,3, 2]]
a.each {|x| p x.depthen}


[2, [3, 3, [4, [5], 4, 4]]]
[2, [3, [[5]], 3], 2]


Have fun,

Jesus.