四川大学期末考试试题（闭卷）
（2009~2010学年第1学期）
课程号： 311036030课程名称： 数据结构与算法分析（A卷） 任课教师： 孙界平，张卫华
适用专业年级： 软件工程 2008级 学号： 姓名：
考试须知 四川大学学生参加由学校组织或由学校承办的各级各类考试，必须严格执行《四川大学考试工作管理办法》和《四川大学考场规则》。有考试违纪作弊行为的，一律按照《四川大学学生考试违纪作弊处罚条例》进行处理。 四川大学各级各类考试的监考人员，必须严格执行《四川大学考试工作管理办法》、《四川大学考场规则》和《四川大学监考人员职责》。有违反学校有关规定的，严格按照《四川大学教学事故认定及处理办法》进行处理。 题 号 一(40%) 得 分 阅卷时间 二(8%) 三(42%) 四(10%) 卷面成绩 注意事项：1. 请务必将本人所在学院、姓名、学号、任课教师姓名等信息准确填写在试题纸和添卷纸上；
2. 请将答案全部填写在本试题纸上；
3. 考试结束，请将试题纸、添卷纸和草稿纸一并交给监考老师。
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一、单项选择题（本大题共20小题，每小题2分，共40分）提示：在每小题列
出的备选项中只有一个是符合题目要求的，请将其代码写到答题纸上。错选、多选或未选均无分。
1. An algorithm must be or do all of the following EXCEPT:
a) correct
b) composed of concrete steps *c) ambiguous d) composed of a finite number of steps e) terminate
2. For set P, the notation |P| indicates
*a) The number of elements in P. b) The inverse of P. c) The powerset of P. d) None of the above.
3. Pick the growth rate that corresponds to the most efficient algorithm when n = 4.
a) 5n
b) 20 log n c) 2n^2 *d) 2^n
注：字迹务必清晰，书写工整。
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4. When the upper and lower bounds for an algorithm are the same, we use:
a) big-Oh notation. b) big-Omega notation. *c) Theta notation. d) asymptotic analysis. e) Average case analysis. f) Worst case analysis.
5. As compared to the linked list implementation for lists, the array-based list implementation requires:
a) More space b) Less space
*c) More or less space depending on how many elements are in the list.
6. When comparing the doubly and singly linked list implementations, we find that the doubly linked list implementation
*a) Saves time on some operations at the expense of additional space. b) Saves neither time nor space, but is easier to implement.
c) Saves neither time nor space, and is also harder to implement.
7. The correct traversal to use on a BST to visit the nodes in sorted order is:
a) Preorder traversal. *b) Inorder traversal. c) Postorder traversal.
8. When every node of a full binary tree stores a 4-byte data field, two 4-byte child pointers, and a 4-byte parent pointer, the overhead fraction is approximately:
a) one quarter. b) one third. c) one half. d) two thirds.
*e) three quarters. f) none of the above.
9. If a node is at position r in the array implementation for a complete binary tree, then its right child is at:
a) (r - 1)/2 if r > 0
b) 2r + 1 if (2r + 1) < n *c) 2r + 2 if (2r + 2) < n d) r - 1 if r is even e) r + 1 if r is odd.
10. The Huffman coding tree works best when the frequencies for letters are
a) Roughly the same for all letters.
*b) Skewed so that there is a great difference in relative frequencies for various letters.
11. A topological sort requires all of the following except:
a) The graph be directed.
b) The graph contain no cycles.
*c) The graph contain weights on the edges.
注：字迹务必清晰，书写工整。
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12. When sorting n records, Mergesort has worst-case cost:
a) O(log n). b) O(n).
*c) O(n log n). d) O(n^2) e) O(n!)
f) None of the above.
13. As compared to the time required to access one unit of data from main memory, accessing one unit of data from disk is:
a) 10 times faster. b) 1000 times faster. c) 1,000,000 time faster. d) 10 times slower. e) 1000 times slower.
*f) 1,000,000 times slower.
14. The basic unit of I/O when accessing a disk drive is:
a) A byte. *b) A sector. c) A cluster. d) A track. e) An extent.
15. The most time-consuming part of a random access to disk is usually:
*a) The seek.
b) The rotational delay.
c) The time for the data to move under the I/O head.
16. Which is generally more expensive?
a) A successful search. *b) An unsuccessful search.
17. The 80/20 rule indicates that:
a) 80% of searches in typical databases are successful and 20% are not. *b) 80% of the searches in typical databases are to 20% of the records. c) 80% of records in typical databases are of value, 20% are not.
18. Hashing is most appropriate for:
a) In-memory applications. b) Disk-based applications.
*c) Either in-memory or disk-based applications.
19. The primary key is:
*a) A unique identifier for a record.
b) The main search key used by users of the database. c) The first key in the index.
20. Depth-first search is best implemented using:
注：字迹务必清晰，书写工整。
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