输出：[3,1,2,1,1,0]
ISS astronauts begin journey back to Earth in Nasa’s first ever medical evacuation
，详情可参考Line官方版本下载
The tree starts as a single region covering the whole space. As points arrive, they get dropped into the region that contains them. When a region exceeds its capacity (the maximum number of points it can hold before splitting), the region divides into four children, and the existing points get redistributed.