Implement a city database using the point quadtree. Each database record contains the name of the city (a string of arbitrary length) and the coordinates of the city expressed as integer x- and...

Implement a city database using the point quadtree. Each database record contains the name of the city (a string of arbitrary length) and the coordinates of the city expressed as integer x- and y-coordinates. Your database should allow records to be inserted, deleted by name or coordinate, and searched by name or coordinate. You should also support region queries, that is, a request to print all records within a given distance of a specified point.