How to derefrence a vector

I was trying a question but i face difficulty in dereferencing the vector here
int maxCities(vector<vector> &a, int n, int m)

Hey @siddhant_samal what do you want to initialise at place of vector vector

I hope I’ve cleared your doubt. I ask you to please rate your experience here
Your feedback is very important. It helps us improve our platform and hence provide you
the learning experience you deserve.

On the off chance, you still have some questions or not find the answers satisfactory, you may reopen
the doubt.