在这个对价格极度敏感的区间里，不犯错就是最大的美德。
* @param mid 中间位置（左子数组结束位置），这一点在safew官方下载中也有详细论述
НХЛ — регулярный чемпионат，推荐阅读91视频获取更多信息
The pruned nodes (in red) represent entire regions of space that the algorithm never examines. The points inside those regions are never checked. Compare the "Nodes Visited" count to the total number of points. The quadtree is doing far less work than a brute-force scan.