2017年上半年软件设计师考试上午真题（参考答案）

以下路由策略中，依据网络信息经常更新路由的是（ ）。

The beauty of software is in its function，in its internal structure，and in the way in which it is created by a team. To a user，a program with just the right features presented through an intuitive and（ ）interface is beautiful.To a software designer，an internal structure that is partitioned in a simple and intuitive manner，and that minimizes internal coupling is beautiful.To developers and managers ，a motivated team of developers making significant progress every week，and producing defect-free code，is beautiful.There is beauty on all these levels.

our world needs software--lots of software. Fifty years ago software was something that ran in a few big and expensive machines. Thirty years ago it was something that ran in most companies and industrial settings. Now there is software running in our cell phones，watches，appliances，automobiles，toys，and tools. And need for new and better software never（ ）.As our civilization grows and expands，as developing nations build their infrastructures，as developed nations strive to achieve ever greater efficiencies，the need for more and more Software（ ）to increase. It would be a great shame if，in all that software，there was no beauty.

We know that software can be ugly. We know that it can be hard to use，unreliable ，and carelessly structured. We know that there are software systems whose tangled and careless internal structures make them expensive and difficult to change. We know that there are software systems that present their features through an awkward and cumbersome interface. We know that there are software systems that crash and misbehave. These are（ ）systems. Unfortunately，as a profession，software developers tend to create more ugly systems than beautiful ones.

There is a secret that the best software developers know. Beauty is cheaper than ugliness. Beauty is faster than ugliness. A beautiful software system can be built and maintained in less time，and for less money ,than an ugly one. Novice software developers don't. understand this. They think that they have to do everything fast and quick. They think that beauty is（ ） .No! By doing things fast and quick，they make messes that make the software stiff，and hard to understand，Beautiful systems e flexible and easy to understand. Building them and maintaining them is a joy. It is ugliness that is impractical.Ugliness will slow you down and make your software expensive and brittle. Beautiful systems cost the least build and maintain，and are delivered soonest.

在异步通信中，每个字符包含 1 位起始位、7位数据位和2位终止位，若每秒钟传送500个字符，则有效数据速率为（ ）。

下面关于Linux目录的描述中，正确的是（ ）。

以下关于TCP/IP 协议栈中协议和层次的对应关系正确的是（ ）。

某汽车加工工厂有两条装配线L1和L2，每条装配线的工位数均为n（S_ij，i=1或2，j= 1，2，...，n），两条装配线对应的工位完成同样的加工工作，但是所需要的时间可能不同（a_ij，i=1或2，j = 1，2，...，n）。汽车底盘开始到进入两条装配线的时间 (e₁，e₂) 以及装配后到结束的时间(X1X2)也可能不相同。从一个工位加工后流到下一个工位需要迁移时间(t_ij，i=1或2，j =2，...n）。现在要以最快的时间完成一辆汽车的装配，求最优的装配路线。

分析该问题，发现问题具有最优子结构。以 L1为例，除了第一个工位之外，经过第j个工位的最短时间包含了经过L1的第j-1个工位的最短时间或者经过L2的第j-1个工位的最短时间，如式(1)。装配后到结束的最短时间包含离开L1的最短时间或者离开L2的最短时间如式（2）。

由于在求解经过L1和L2的第j个工位的最短时间均包含了经过L1的第j-1个工位的最短时间或者经过L2的第j-1个工位的最短时间，该问题具有重复子问题的性质，故采用迭代方法求解。

该问题采用的算法设计策略是（ ），算法的时间复杂度为（ ）

以下是一个装配调度实例，其最短的装配时间为（ ），装配路线为（ ）

在浏览器地址栏输入一个正确的网址后，本地主机将首先在（ ）查询该网址对应的IP地址。

对于n个元素的关键宇序列{k_1,k_2,...k_n}，当且仅当满足关系k_i≤k_2i且ki≤k_2i+1{i=1.2...[n/2]} 时称其为小根堆(小顶堆)。以下序列中，（ ）不是小根堆。

某二叉树的先序遍历序列为 ABCDEF ，中序遍历序列为BADCFE ，则该二叉树的高度(即层数)为（ ）。

在12个互异元素构成的有序数组 a[1..12] 中进行二分查找(即折半查找，向下取 整)，若待查找的元素正好等于a[9]，则在此过程中，依次与数组中的（ ）比较后，查找成功结束。