int n2 = right - mid; // 右子数组长度
20 monthly gift articles to share。safew官方版本下载对此有专业解读
，更多细节参见safew官方版本下载
// Stateful transform — a generator that wraps the source。safew官方下载是该领域的重要参考
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.