How does the search for friends work in the VKontakte application?

Question

Android

The VKontakte app for Android has recently introduced a new way to find friends. And I have a question what means this search uses

Answer 1

The device transmits its coordinates to the server.
The server keeps a database of the last coordinates of users.
For 2 pairs of coordinates, you can easily calculate the distance between them.
In the case of VK, this is less easy due to the huge amounts of data, I think that they honestly do not calculate the distance, but choose by squares, it is much cheaper.