A problem is in P if it can be solved quickly by a computer, and in NP if a solution can be verified quickly.
Every decision we make today impacts the health of our oceans tomorrow.
"The best time to plant a tree was 20 years ago. The second best time is now."
Life is too short to be anything but happy.
每一种化学结合完全且仅仅依赖于两种对立的力量,即正电和负电。