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。
正义不是目的地，而是一段旅程。
Sometimes you just have to take a leap of faith and believe in yourself.
A people without children would face a hopeless future; a country without trees would face a future with even less hope.
The best way to predict the future is to invent it.
In the quest for understanding the cosmos, every question answered leads to a dozen more.
