Say I have a collection of users, and I want to check if users are in two different cities based on their ip address.
Do I actually have to keep a database mapping IP group -> City? Is there a more efficient way to do this?
I'm not concerned which cities the users are from, just the question of whether they're from different cities. And it doesn't have to be totally exact either, I'd be comfortable with a high percentage chance of the users being in different cities.
Any advice would be appreciated.
