问题 单项选择题

已知某带权图G的邻接表如下所示,其中表节点的结构为:则图G是()。

 

A.无向图

B.完全图

C.有向图

D.强连通图

答案

参考答案:C

解析:

完全图是每对顶点之间都恰连有一条边的简单图。n个端点的完全图有n个端点及n(n-1)/2条边。强连通图(StronglyConnectedGraph)是指一个有向图(DirectedGraph)中任意两点v1、v2间存在v1到v2的路径(path)及v2到v1的路径的图。

从上面的表结构可以看出,有v1→v3的边,但没有v3→v1的边,显然这不是无向图,也不是完全图和强连通图,只能是有向图。

阅读理解

阅读短文,根据要求完成下面各小题。

     3. For those of us who are studying at school, the time of exams is very stressful and difficult. Some

people find exam times so bad that they become ill, because they are afraid of failing; they are afraid of

letting their parents and family down. If exams are really making you ill or worried, don't hide your feelings.

Talk to someone about it. Maybe you can speak to a friend, or someone in your family, or teachers at your

place of study. If one person doesn't help you, ask someone else.

     How to get through exams? Here are some advice:

     Ask a teacher or tutor about how to review your lessons, and exam skills-how to work when you are in

an exam.

     Take short rests during your time of work. If your mind is tired, it will not remember well.

     Plan your work: study at times when you know you will work at your best.

     Get enough sleep, and eat healthy food.

     You need exercise to work well. Walk, run, play sport-whatever you enjoy.

     Stop thinking about the future and failing.

     If you feel ill, talk to someone about your worries. But don't be too relaxed! 4. Some stress over exams

makes you work hard for them.

     If it upsets you to talk to your friends about an exam when it is finished, don't do it! In fact, don't even

think about the exam you have finished. What is done is done. You cannot change what you have written!

     To this advice, we could add:

     If you are studying in the evening, don't go straight to bed. Your mind will still be "going round and round"

-thinking too much. Do something else, maybe walk or get exercise. Choose something that will relax you,

and make you think of other things.

(一)根据短文内容简要回答问题。

1. Why do some students hate exams?

    ______________________________________________________________________

2. What should you do if the exam upsets you when it is finished?

    ______________________________________________________________________

(二)将短文中划线的句子译成汉语。

3. ______________________________________________________________________

4. ______________________________________________________________________

(三)请给短文拟一个适当的标题。

5. ______________________________________________________________________

填空题