问题 单项选择题

某一非确定性有限自动机(NFA)的状态转换图如图2-6所示,与该NFA等价的正规式是(16),与该NFA等价的DFA是 (17)
[*]

A.

B.


C.

D.

答案

参考答案:A

解析:

[分析]: 从q0状态可以经过q1状态回到q0状态,同时也可以输入0回到q0状态,或输入若干个0后经过q1状态再回到q0状态。所以该自动机识别的串等价于正规式(0|10)*。再利用子集法求出与该NFA等价的DFA。

阅读理解

阅读理解。

      A friend's grandfather went to America from Eastern countries. After he was processed (移民入境检查) at

Ellis Island, he went into cafeteria (自助餐厅) in lower Manhattan to get something to eat. He sat down at an

empty table and waited for a waiter to take his order. Of course no waiter came at all. At last, a woman held a

plate full of food and sat down opposite him. When she saw the old man without any food, she told him how a

cafeteria worked.

      "Start out at that end," she said, "Just go along the line and pick out what you want. At the other end they'll

tell you how much you have to pay. After you pay for the food, you can bring it here and eat it." 

      "I soon knew how everything works in America," the grandfather told a friend. "Life is like a cafeteria here.

You can get everything you want only if you are willing to pay the money. You can even get success, but you'll

never get it if you wait for someone to bring to you. You have to get up and get it by yourself."

1. Maybe the old man came from _______. [ ]

A. Poland

B. India

C. Canada

D. Egypt (埃及)

2. Who came when he sat down at an empty table? [ ]

A. A waiter

B. A man

C. A woman

D. No person

3. From the text, we know if you want to get success in America, you should _______. [ ]

A. get help from your friend

B. know how a cafeteria works

C. get up again if you fail

D. try to get it by yourself

4. At last, the grandfather _______.[ ]

A. got the food himself

B. was very angry with the waiter

C. had the woman's food

D. had nothing to eat

5. Which is the best title for the passage? [ ]

A. From Eastern countries to America

B. Life is like a cafeteria in America

C. How to eat in a cafeteria

D. Eating in America

单项选择题