On Dec 23, 10:09 pm, Mark <mnbaya...@gmail.com> wrote:
> I'm trying to figure out the best way to go about doing this.
> I have a "map" for a game, which I'd like to store in a matrix. Some
> cells will be empty (NULL), and some will hold objects.
> I need a matrix so that I can quickly find neighboring cells.
> However, when create this map, I don't know what size it is going to
> be, so it needs to be expandable. I also don't know which direction
> it's going to grow in, so starting at [0][0] and expanding as
> necessary won't work either, because I may later need to use [-1][0].
> I don't really care if the indices are re-written if I try to access a
> negative index. (ie, if I try to insert something into [-1][0], if it
> increased all the indices by 1 so it didn't have a negative index,
> that would be fine).
> I just need something that's simple to implement, and preferably has
> little overhead. I was contemplating using something like
> std::vector<vector<myClass> > but that wouldn't fill the negative
> index requirement, would it? Are there any other suggestions?

Another option would be an std::map with the indices you choose
(including negative):

std::map< int, std::map< int, yourClass >>

it should perform fairly well as it is an highly optimized balanced
tree of some sort (red/black maybe??).