[Coursera OA] some problems

http://www.1point3acres.com/bbs/forum.php?mod=viewthread&tid=206601&highlight=coursera%2BOA

http://www.1point3acres.com/bbs/forum.php?mod=viewthread&tid=292538&highlight=coursera%2BOA

http://www.1point3acres.com/bbs/forum.php?mod=viewthread&tid=283414&highlight=coursera%2BOA

http://www.1point3acres.com/bbs/forum.php?mod=viewthread&tid=203180&highlight=coursera%2BOA

http://www.1point3acres.com/bbs/forum.php?mod=viewthread&tid=200397&highlight=coursera%2BOA

http://www.1point3acres.com/bbs/forum.php?mod=viewthread&tid=206662&highlight=coursera%2BOA

[Coursera OA] some problems

原文：http://www.cnblogs.com/Gryffin/p/7523761.html