QuadTree find neighbor

Question

I'm searching for a algorithm to find neighbors of a quadtree, in the example image, I got the red node, how to find the blue nodes. Any ideas?

Answer 1

There are some known algorithms. Check them out.

1. Kunio Aizawa et al. - Constant Time Neighbor Finding in Quadtrees: An Experimental Result
2. Kasturi Varadarajan - All Nearest Neighbours via Quadtrees
3. Robert Yoder, Peter Bloniarz - A Practical Algorithm for Computing Neighbors in Quadtrees, Octrees, and Hyperoctrees