NSData and CFData
NSData *my_nsdata = (__bridge_transfer NSData*)my_cfdata; // -1 on the my_cfdata
or
NSData *my_nsdata = (__bridge NSData*)my_cfdata; // no adjustment of retain counts.
NOI-001—《C++编程及竞赛训练》
NOI-002—《普及组竞赛强化训练课程》
NOI-003—《初级算法课程》