A way to make CIN and scanf as fast as possible:

Cin Slow is a reason, in fact, the default time, CIN and stdin always keep in sync, that is to say, these two methods can be mixed, without worrying about the file pointer confusion, and cout and stdout are the same, the two mixed will not output order confusion. Because of this compatibility feature, CIN has a lot of extra overhead and how to disable this feature. Just one statement Std::ios::sync_with_stdio (false), so you can cancel the synchronization of CIN to stdin.
(Transferred from http://blog.csdn.net/yujuan_mao/article/details/8119529)

That is, add a sentence before the program, CIN efficiency and scanf almost.

Ios::sync_with_stdio (FALSE);