He had persuaded his science teacher to help him make a makeshift rocket. Somehow, he had managed to get his hands on the ingredients for gunpowder - potassium nitrate, sulphur and charcoal.
The efficiency depends on the query size relative to the data distribution. A small query in a sparse region prunes almost everything. A query that covers the whole space prunes nothing (because every node overlaps), degenerating to a brute-force scan. The quadtree gives you the most benefit when your queries are spatially local, which is exactly the common case for map applications, game physics, and spatial databases.
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靠山吃山唱山歌，靠海吃海念海经。各展其长的特色产业背后，是乡村全面振兴的坚实步伐，蕴含着总书记一以贯之的引领推动。
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