一个问题如果在计算机上可以快速解决，那么它属于P类问题；如果一个解可以快速验证，那么它属于NP类问题。
A problem is in P if it can be solved quickly by a computer, and in NP if a solution can be verified quickly.
This part of my life,this little part is called "happiness".
我不在乎名声。我在乎的是工作。