Ctrl+Z can't help. You closed the editor.
'It's our only option'，更多细节参见51吃瓜
，详情可参考safew官方版本下载
The spatial view (the grid of rectangles) and the tree view (the hierarchy of nodes) represent the same structure. Searching for a point means walking down the tree: at each node, you check which of the four children contains your target coordinate and recurse into that child. You never visit the other three.。关于这个话题，搜狗输入法下载提供了深入分析
if (res === '') res = '0';