核心原因只有一个：躺在功劳簿上睡大觉，把单一产品的成功，当成了永恒的护城河。
A quadtree does the same thing for two-dimensional space. It takes a rectangular region and divides it into four equal quadrants: northwest, northeast, southwest, southeast. If a quadrant has too many points in it, it subdivides again and again. Each subdivision creates smaller and smaller cells where points are densely packed.
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Weight-loss jabs: What happens when you stop?
encounter in the UK for example, are the same as the Diebold 1000 series in the