NP完全性的概念为理解问题的复杂性提供了一个强大的工具。
The concept of NP-completeness has provided a powerful tool for understanding the complexity of problems.
有些怪异的人性总想把简单的事情弄得复杂。
The only meaningful way to study learning is through objective measurement.
"The very least you can do in your life is to figure out what you hope for. And the most you can do is live inside that hope. Not admire it from a distance but live right in it, under its roof."