2005 Academic Challenge

Transcription

1 2005 Academic Challenge COMPUTER SCIENCE TEST - SECTIONAL Computer Science Test Production Team Sanjay Madria, University of Missouri at Rolla Author/Team Coordinator S. R. Subramanya, University of Missouri at Rolla Author Scott Elliott, John A. Logan College Reviewer Don Wayman, WYSE Coordinator of Test Production GENERAL DIRECTIONS Please read the following instructions carefully. This is a timed test; any instructions from the test supervisor should be followed promptly. The test supervisor will give instructions for filling in any necessary information on the answer sheet. Some Academic Challenge test sites may use answer sheets that require you to fill in the letter of the answer you choose on the blank line after each question number. Others will ask you to indicate your answer to each question by marking an oval that corresponds to the correct answer for that question. Only one oval should be marked to answer each question. Multiple ovals will automatically be graded as an incorrect answer. Be sure ovals are marked as. Not as,,, etc. Test Question - 1. Which of the following was formed by the New Madrid Earthquakes of ? Answer Sheet - 1. a. Lake of the Ozarks (MO) b. Little Grassy Lake (IL) c. Kentucky Lake (KY) d. Reelfoot Lake (TN) e. Crater Lake (OR) A B C E If you wish to change an answer, erase your first mark completely before marking your new choice. You are advised to use your time effectively and to work as rapidly as you can without losing accuracy. Do not waste your time on questions that are too difficult for you. Go on to the other questions and come back to the difficult ones later if you can. *** TIME: 40 MINUTES *** DO NOT OPEN TEST BOOKLET UNTIL YOU ARE TOLD TO DO SO! 2005 Worldwide Youth in Science and Engineering WYSE, Worldwide Youth in Science and Engineering and the WYSE Design are service marks of and this work is Copyright 2005 Board of Trustees of the University of Illinois at Urbana - Champaign. All rights reserved.

2 WYSE Academic Challenge Computer Science Test (Sectional) The following measurements have been made after the execution of a program P on the machine: CPU Execution time is 7 sec, Instructions executed are 28 x 10 8, and CPI (Cycle Per Instruction) is 2. What is the clock rate? a. 800 MHz b. 60 MHz c. 1.8 MHz d. 100 MHz 2. Which of the following statements about Cyclic Redundancy Check (CRC) is TRUE? a. It is a common error-checking protocol used in modems. b. It is a form of a hash function. c. It is based on the algebra of polynomials over the integers (mod 2). d. It is a reliable method for detecting data transmission errors. e. All of the above. 3. Which of the following expressions is equivalent to NOT(NOT(X OR Y) OR NOT(X OR NOT Y)), regardless of the actual Boolean values of X and Y? a. X b. (X OR Y) c. (X AND Y) d. (X AND (NOT Y)) 4. In object-oriented programming concept, inheritance is a. permitting objects to be defined and created that are specialized types of already existing objects. b. to ensure that objects cannot change the internal state of other objects in unexpected ways. c. the property that a message can mean different things depending on the object receiving it. d. the process of extracting the relevant properties of an object while ignoring nonessential details. e. All of the above.

3 Computer Science 2 5. Which of the following is true about XML (Extensible Markup Language)? a. XML can have user define markups. b. It is a subset of SGML (Standard Generalized Markup Language). c. XML can store data as well as documents. d. XML can model semi-structured data. e. All of the above. 6. Let k be an integer greater than 1. Which of the following represents the order of growth n i of the expression ( k + 1) as a function of n? i= 1 n a. Θ (( k + 1) ) nlogn b. Θ (( k + 1) ) n c. Θ (( k + 1) log n) 2kn d. Θ ( k ) e. Θ( n k+1 ) 7. Consider the following programming segment in pseudocode: X := 1; Y := 1; WHILE (X <= 1000) BEGIN X := 2 X + 2 Y ; Y := Y + 1; END; What will be the value of Y at the end of the pseudocode? a. 3 b. 4 c. 5 d. 6 e. 7

4 Computer Science 3 8. Which of the following represents a postorder traversal of T? T P Q V W Z Y U a. U X W Q Z Y V P b. X U W Q P V Z Y c. X U W Q Z Y V P d. P Q V W Z Y U X e. Q U X W P Z V Y X 9. Of the following five conditions, which are necessary for a deadlock to exist in an operating system? I. Hold and wait II. Circular wait III. No paging IV. No preemption V. Mutual exclusion a. I and II b. II, III and IV c. I, II, III and IV d. I, II, IV and V e. All of the above 10. In a relational data model, a loss-less join operation is always performed on: a. a primary key and a foreign key attribute. b. any two given attributes. c. any attribute which is common in two relations to be joined. d. any attributes provided they draw the values from different domains. e. All of the above

5 Computer Science Given the Boolean variable assignments X = TRUE, Y = FALSE, and Z = FALSE, what can you say about the value of the expression (NOT ((X OR Y) AND ((NOT (Y AND Z)) AND X)))? a. It is TRUE. b. It is FALSE. c. The expression is syntactically incorrect and cannot be evaluated. d. Not enough information is given to evaluate the expression. 12. Parallel Processing refers to the concept of speeding-up the execution of a program by dividing the program into multiple fragments that can execute simultaneously, each on its own processor. A program being executed across n processors might execute n times faster than it would use a single processor. Below are five precedence graphs for a set of tasks to be executed on a parallel processing system S as shown below: Start T1 T2 T3 T4 T5 T6 T7 T8 End Graph 1 Start T1 T2 T3 T4 T5 T6 T7 T8 End Graph 2 Start T1 T2 T3 T4 End T5 T6 T7 T8 Graph 3 T1 T2 Start T3 T5 T4 T6 End Start T1 T3 T2 T4 T7 T8 End T7 T8 T5 T6 Graph 4 Graph 5 System S has four processors (CPU s). If each of the tasks T1,,T8 takes the same unit time, which precedence graph could be executed with fastest speed on S? a. Graph 1 b. Graph 2 c. Graph 3 d. Graph 4 e. Graph 5

6 Computer Science Which of the following type of memory is fastest in a computer? a. RAM b. Cache c. CPU register d. Magnetic disk e. Magnetic tape 14. The binary representation of hexadecimal number 14F is: a b c d The parameter seek time in reference to accessing data on disk is the: a. time taken by disk to send the required data to the CPU. b. time taken by the computer to send the request to the CPU. c. time the user must wait for the beginning of the required block to rotate into the position under the read/write head. d. time needed to mechanically position the read/write head on the correct track. 16. Which of the following data structures is most appropriate when an electrician wants to put electric cable in your house? a. Heap b. Binary Tree c. Graph d. Linked list

7 Computer Science Assume that S and T are instances of a class Queue, and are both initially empty. What does Queue T look like (from Front to Rear) after the following sequence of operations? S.ENQUEUE (6); S.DEQUEUE ( ); T.ENQUEUE (2); T.ENQUEUE (9); T.ENQUEUE (5); T.DEQUEUE ( ); S.ENQUEUE (3); S.ENQUEUE (1); T.ENQUEUE (4); a b c d File Allocation Table (FAT) is: a. a table that indicates the virtual location on secondary storage of the space allocated to a file. b. a table that indicates the physical location on main memory of the space allocated to a file. c. a table that indicates the physical location on cache memory of the space allocated to a file. d. a table that indicates the physical location on secondary storage of the space allocated to a file. 19. Job control language (JCL) is: a. a language that is designed to express statements in a job that are used to identify the job to an operating system. b. nothing but JAVA programming language. c. a C programming language. d. a Fortran programming language.

8 Computer Science A "strictly" binary tree is a binary tree in which every node has either 0 or 2 children (i.e. no node has exactly 1 child). How many nodes are in a strictly binary tree that has 8 leaves? a. 7 b. 8 c. 15 d Consider the following function: Function Add(Int N) BEGIN End; IF (N <= 1) BEGIN END; ELSE BEGIN End; RETURN 0; RETURN (N + Add(N - 1) + Add(N - 2)); What value is returned by the call Add(4)? a. 0 b. 4 c. 6 d. 9 e. 11

9 Computer Science Consider the binary search tree shown below. This tree could be the result of inserting letters into an empty binary search tree in any of the following orders EXCEPT: H C W E P K Q a. H W P C E Q K b. H C E W P K Q c. H W P K C E Q d. H W P Q C K E e. H C E W K P Q 23. The following integers are read in the order indicated and inserted into a binary search tree with smaller elements inserted in the left subtree and larger elements inserted in the right subtree: What would be output if this tree was printed using a postorder traversal? a b c d e

10 24. Consider the following expression: (A > B) && (C <= B) Computer Science 9 Assume that A, B, and C are integer variables. Which of the expressions given below is (are) equivalent to the one given above? I.!(A < B) &&!(C >= B) II. (A > B) && (B > C) III.!((A <= B) (B < C)) a. I only b. II only c. III only d. I and III e. II and III 25. Consider the following function: Int Strange(Int N) BEGIN END. IF (N <= 1) ELSE RETURN 1; BEGIN RETURN (Strange(N - 2) + 1); END; Which of the following replacements for the line containing the recursive call returns the same value as the original version of function Strange? (Assume N is even). a. RETURN 1; b. RETURN (n / 2-1); c. RETURN (n / 2 + 1); d. RETURN (n + 1); e. RETURN (n / 2);

11 26. In Europe and Asia, the most common used technology for cellular communication is currently: a. TDMA b. FDMA c. GSM d. CDMA e. None of the above 27. In cryptography, digital signature is a concept where a sender uses a: a. private key of receiver to create the signature. b. public key of receiver to create the signature. c. public key of itself to create the signature. d. private key of itself to create the signature. Computer Science The adjacency-list representation of a graph G = (V, E) consists of an array Adj of V lists, one for each vertex in V. For each u V, the adjacency list Adj[u] contains all the vertices v such that there is an edge (u, v) E. Let G = (V, E) be a finite directed acyclic graph with E > 0. Which of the following must be true? I. The sum of the lengths of all the adjacency lists is E. II. The sum of the lengths of all the adjacency lists is 2 E. III. G has a vertex with no incoming edge. a. I only b. II only c. III only d. I and III only e. II and III only

12 Computer Science The circuit below represents which of the following equations? A B C D a. ((NOT A) AND (NOT B)) OR (NOT A AND C AND (NOT D)) b. (A AND B) OR (A AND C AND D) c. ((NOT A) AND (NOT B)) OR (NOT (A AND C AND (NOT D))) d. ((NOT A) AND (NOT B)) OR (A AND C AND (NOT D)) e. None of the above 30. Which number represents the largest decimal value? a. A3 16 b c d. AF 16 e