The algorithm maintains a running "best distance" that starts at infinity. As it walks the tree, it checks each visited point and updates the best distance if it finds something closer. Before recursing into a child node, it checks whether the closest possible point in that child's bounding box is farther than the current best. If so, the entire subtree gets pruned.
// 3. 从后向前遍历，稳定排序的关键！
，详情可参考WPS官方版本下载
结语：多层级的文明死结好了，写了6000多字，我们追寻答案的洋葱终于剥完了。
《非穷尽列举》定档 3 月 8 日