* 时间O(n) 空间O(n)（理论最优，无冗余计算/存储）
Update Impracticality: The extensive pre-processing for CH makes it unsuitable for frequent updates, let alone OsmAnd’s goal of supporting near real-time changes through hourly map updates.
，这一点在safew官方版本下载中也有详细论述
includes, as standard, a 9600 bps SDLC modem for connection to the host, and a
Nasa's mega rocket has been moved to the launch pad in Cape Canaveral, Florida, as the final preparations get underway for the first crewed mission to the Moon in more than 50 years.