public Point2D nearest(final Point2D p) {
if (isEmpty()) {
return null;
}
Holder<Point2D> nearest = new Holder<>(root.key);
nearest(root, nearest, p, true);
return nearest.value;
}
private void nearest(
final Node node, final Holder<Point2D> nearest, final Point2D p, final boolean vertical) {
if (node == null) {
return;
} else if (node.key.compareTo(p) == 0) {
nearest.value = node.key;
return;
} else if (p.distanceTo(node.key) < p.distanceTo(nearest.value)) {
nearest.value = node.key;
}
if (onTheLeft(p, node.key, vertical)) {
nearest(node.left, nearest, p, !vertical);
if (distanceToVertical(p, node.key, vertical) < p.distanceTo(nearest.value)) {
nearest(node.right, nearest, p, !vertical);
}
} else if (onTheRight(p, node.key, vertical)) {
nearest(node.right, nearest, p, !vertical);
if (distanceToVertical(p, node.key, vertical) < p.distanceTo(nearest.value)) {
nearest(node.left, nearest, p, !vertical);
}
}
}