问题 单项选择题

下列叙述中正确的是().

A.算法的效率只与问题的规模有关,而与数据的存储结构无关

B.算法的时间复杂度是指执行算法所需要的计算工作量

C.数据的逻辑结构与存储结构是一一对应的

D.算法的时间复杂度与空间复杂度一定相关

答案

参考答案:B

解析:

算法的复杂度主要包括时间复杂度和空间复杂度。通常用时间复杂度和空间复杂度来衡量算法效率,算法的时间复杂度就是执行该算法所需要的计算工作量;算法所执行的基本运算次数与问题的规模有关。而一个算法的空间复杂度,就是执行该算法所需要的内存空间;一般来说,一种数据的逻辑结构根据需要可以表示成多种存储结构。

阅读理解

阅读理解

     Everyone has good days and bad days.

     Sometimes, you feel as if you're on top of the world.But occasionally you feel horrible, and you lose

things and you cannot focus on your schoolwork.

     For more than 20 years, scientists have suggested that high selfesteem (自尊) is the key to success.

Now, new research shows that focusing just on building selfesteem may not be helpful.In some cases,

having high selfesteem can bring bad results if it makes you less likeable or more upset when you fail at

something.

     "Forget about selfesteem, " says Jennifer Crocker, a psychologist (心理学家) at the University of

Michigan, US, "It's  not the important thing."

     Feeling good

     Crocker's advice may sound a bit strange because it is good to feel good about yourself.

     Studies show that people with high selfesteem are less likely to be depressed, anxious, shy, or lonely

than those with low selfesteem.

     But, after reviewing about 18,000 studies on selfesteem, Roy Baumeister, a psychologist at Florida

State University, has found that building up your selfesteem will not necessarily make you a better person.

     He believes that violent and wicked (邪恶的) people often have the highest selfesteem of all.He also

said:"There's no evidence that kids with high selfesteem do better in school."

     Problems

     All types of people have problems.People with high selfesteem can have big egos (自我) that can

make them less likeable to their peers (同龄人), said Kathleen Vohs, a psychology professor at

Columbia University.

     People with high selfesteem tend to think more of themselves, Vohs says.People with low selfesteem

are more likely to rely on their friends when they need help.

    What to do

     Researchers say it is best to listen to and support other people.Find positive ways to contribute to

society.If you fail at something try to learn from the experience."The best therapy (药方) is to recognize

your faults, " Vohs says."It's OK to say, I'm not so good at that, and then move on."

1. It is concluded in the research that high selfesteem________.

A. is not important at all

B. has taken on a different meaning

C. may not be the key to success

D. does not help you do better at school

2. According to the research, people with high selfesteem________.

A. have better relationship with people of their own age

B. are more likely to become violent and wicked

C. tend to be proud and do not care much about others

D. often feel depressed and can't focus on their work

3. The advice in the last paragraph is mainly for people________.

A. with high selfesteem  

B. with low selfesteem

C. who are still at school  

D. who are good at everything

单项选择题