说明：  你已经熟悉STL了。你知道怎样创建容器、怎样遍历容器中的内容，知道怎样添加和删除元素，以及如何使用常见的算法，比如find和sort。但是你并不满意。你总是感到自己还不能充分地利用STL。本该很简单的任务却并不简单；本该很直接的操作却要么泄漏资源，要么结果不对；本该更有效的过程却需要更多的时间或内存，超出了你的预期。是的，你已经知道如何使用STL了，但是你并不能确定自己是否在有效地使用它。
(You are already familiar with the STL. Do you know how to create the container, how to traverse the contents of the container, know how to add and remove elements, and how to use common algorithms, such as find and sort. But you are not satisfied. You always feel that they can not take full advantage of STL. This is the very simple task is not simple the direct manipulation of the very resources they either leak, or is not correct the process the more effective it takes more time or memory than you expected. Yes, you already know how to use the STL, but you are not sure whether to use it effectively.)