Let's say I have the following site structure:root  category1    item1    item2    ....    item99  category2    item101    item102    ....    item199  ...Each category page contain pagination to allow reasonable amount of items on each page. From my point of view I'd keep the sitemap structure as I mentioned above (with out any care of pagination used on categories pages). Is that right approach?
Is there any reason to add pagination to sitemap?
sitemap;pagination
Yes. The pagination would be unnecessary as the sitemap will tell Google where to find all of the item pages. 