冬天已经到来,春天还会远吗?
历史学家必须成为诗人和艺术家,才能赋予过去枯骨以生命。
改变生活:立即开始,华丽地去做,没有例外。
A problem is in P if it can be solved quickly by a computer, and in NP if a solution can be verified quickly.