—— 请按键盘 空白键 开始游戏 ——

"It takes ten times as long to put yourself back together as it does to fall apart."
I believe in such cartography – to be marked by nature, not just to label ourselves on a map like the names of rich men and women on buildings.
We must be free not because we claim freedom, but because we practice it.
A problem is in P if it can be solved quickly by a computer, and in NP if a solution can be verified quickly.