Find in a Quad Tree
find(<x, y>, root) finds the node which has the given pair of keys in it or returns quadrant where the point should be if there is no such node
Node *& find(Key x, Key y, Node *& root) {
return root; // Empty tree
return root; // Key may not actually be here
int quad = getQuadrant(x, y, root);
return find(x, y, root->quadrants[quad]);
Compares against center; always makes the same choice on ties.