The quadtree is the two-dimensional case of a broader family of space-partitioning data structures. Octrees extend the same idea to three dimensions (splitting cubes into eight children), KD-trees use alternating axis-aligned splits (splitting along x, then y, then x again), and R-trees group nearby objects into bounding rectangles. Each variant makes different tradeoffs between construction time, query speed, and update cost.
NYT Strands spangram hint: Is it vertical or horizontal?Today's NYT Strands spangram is vertical.
，更多细节参见同城约会
AnnouncementsPolicy，更多细节参见同城约会
Yellow: Backstabber