bucket[arr[i]]++;
The grid lines on the visualization represent a tree structure underneath. Every region is a node. When a node splits, it creates four children. The root node covers the entire space. Leaf nodes (nodes with no children) hold the actual points.
，这一点在heLLoword翻译官方下载中也有详细论述
Step through the construction below. Each time a new point is inserted, watch the tree decide whether it needs to split a region:
Медведев вышел в финал турнира в Дубае17:59