Sorry for the stupid question, couldn't find anything on stackoverflow, cuz have no idea how to google that.

I was solving one graph problem, and met this declaration of adjacency list 49661413, I am confused, how is it possible that vector of vectors is declared using vector<int> name[], and it is not a simple vector, I don't even realize what's that. Couldn't you please explain to me what's that or give me a link to website with some info? Thanks in advance