问题 单项选择题

下列与算法有关的叙述中,不正确的是( )。

A.运算是数据结构的一个重要方面,运算的实现步骤用算法来描述
B.算法是精确定义的一系列规则,它指出怎样从给定的输入信息经过有限步骤产生所求的输出信息
C.算法的设计采用由粗到细,由抽象到具体的逐步求精的方法
D.对于算法的分析,指的是分析算法运行所要占用的机器时间,即算法的时间代价

答案

参考答案:D

解析: 算法是一系列解决问题的清晰指令,也就是说,能够对一定规范的输入,在有限时间内获得所要求的输出。算法常常含有重复的步骤和一些比较或逻辑判断。如果一个算法有缺陷,或不适合于某个问题,执行这个算法将不会解决这个问题。不同的算法可能用不同的时间、空间或效率来完成同样的任务。一个算法的优劣可以用空间复杂度与时间复杂度来衡量,也就是算法分析,因此选项D错误。算法设计一般呆用由粗到细、由抽象到具体的初步求精的方法。

阅读理解

阅读理解。

Dear Editor (编辑),

     I used to be a doctor in a children's hospital. Sometimes I treated children who had been poisoned (中毒)

by medicines for older family members. The children didn't know the medicine was dangerous; they just knew

it tasted sweet. Children easily opened the bottle that we now use in China.

     Some days ago I talked about medicine with an American. He showed me a kind of plastic bottle. The

design was very quite simple and I'm sure our Chinese factories could produce these bottles. The top of the

bottle locks but can be opened by pressing down on it while turning. This is difficult for most young children

to do, though grown-ups can open these bottles very easily.

     I'm certain that the price of making such tops would be very low. As a doctor, I'd love to see this done.

And most parents would be grateful.

                                                                                                                                               Yours,

                                                                                                                                                Li Hua

1. The writer's job in the hospital was mainly to _____. [ ]

A. treat sick children

B. treat poisoned children

C. give medicine to people

D. give medicine to children

2. The doctor seems to be _____. [ ]

A. happy about China's hospital

B. angry with what has happened

C. anxious to solve the problem

D. pleased with his invention

3. The doctor thinks that we should _____. [ ]

A. study the Americans

B. buy that kind of bottle

C. produce this kind of plastic bottle

D. turn to Americans for help

4. The letter was written to the editor to ask for _____. [ ]

A. money from the newspaper

B. the plastic bottles from the readers

C. medicine from the editor

D. support from the public

问答题 简答题