Does it give you the answer that you expected it to give? Often, in practical problems, you'll spend just as much time doing performance debugging. Why is it slow?

它返回了期待中的结果了么？通常,在实际的问题中你会花，同样多的时间在性能调试上,它为什么运行这么慢？

麻省理工公开课 - 计算机科学及编程导论课程节选