2001 Academic Challenge

Transcription

1 Worldwide Youth in Science and Engineering 2001 Academic Challenge COMPUTER SCIENCE TEST - STATE FINALS Computer Science Test Production Team Fred Hanzelin (retired), South Suburban College Coordinator/Co-author Yixia Lu, South Suburban College Co-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 are using answer sheets that require you to fill in the letter of the answer you choose on the blank line after each question number. Others may 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,,. Test Question - 1. What is the name of the robotic helicopter used for surveillance by th a. Eye in the Sky b. ROBOT I c. Surveyor I d. CYPHER e. Robospierre Answer Sheet-- 1. If you wish to change an completely before marking your new choice. A B C E answer, erase your first mark 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! 2001 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

2 Copyright 2001 Board of Trustees of the University of Illinois at Urbana - Champaign. All rights reserved.

3 WYSE Academic Challenge Computer Science Test (State Finals) The decimal integer -14 stored in 8-bit, 2's-complement form is a b c d The smallest negative integer that can be stored in 8-bit, 2's-complement form is the decimal integer a b c d The difference between the 2's complement integers and is the decimal integer a. 172 b. 250 c. 122 d The difference between the octal numbers 54 and 37 is the hexadecimal number a. 11 b. D c. 17 d. C 5. The result of combining the binary words and using bitwise OR is a b c d

4 Computer Science 2 6. If the clock speed of a processor is 400MHz and an instruction takes 15 nanoseconds to excute, then how many cycles does the instruction take to execute? a. 0.4 b. 6 c d The decimal number converted to a binary number is a b c d The binary number converted to a decimal number is a b. 75 c d Which of the following is equivalent to the boolean expression (NOT((NOT A) AND B)) AND (NOT B)? a. A AND (NOT B) b. A OR (NOT B) c. NOT B d. A OR B 10. In computer pseudocode which of the following statements is not a valid assignment operation? a. a = b b. a = answer + b c. answer = a + b d. a + b = answer

5 Computer Science The boolean expression F = (A AND (NOT B)) OR B is represented by which circuit? a. A B F b. A B F c. A B F d. exactly two of these 12. Which expression is equivalent to the venn diagram below? a. F = (A AND (NOT B)) AND ((NOT B) OR C) b. F = NOT((A AND (NOT B))) AND ((NOT B) OR C) c. F = ((NOT A) OR (NOT B)) AND C d. F = (NOT (A AND B)) AND ((NOT B) OR C)

6 Computer Science The operations AND, OR, and XOR are bitwise operators. What are the values of A and B after the following executes? (The values of A and B are given in binary here.) A =1001, B = 1110 A = A AND B B = A XOR B A = A OR B a. A = 1101, B = 1010 b. A = 0011, B = 1110 c. A = 1110, B = 0110 d. A = 1001, B = If the array A[0..2, 1..4] is stored by columns in your computer with the first element stored at location 50 and each element takes one location to store, then location 60 stores element a. A[1,4] b. A[2,3] c. A[2,2] d. A[0,4]

7 Computer Science R0 is a data register in the Marina computer. The following is a description of a set of assembly language commands for the computer. OPERATION load x, R0 add x, R0 sub x, R0 mul x, R0 div x, R0 sto R0, x DESCRIPTION load the content of RAM location x to R0 add the content of x to R0 subtract x from R0 multiply x to R0 divide x into R0 store the contents of R0 to x The following sequence of Marina statements is equivalent to which assignment? load b, R0 sub c, R0 mul b, R0 add b, R0 div c, R0 sto R0, y a. y = c/b*(b - c) + b b. y = (b*(b - c) + b)/c c. y = c/((b*(b - c) + b)) d. y = b - c*b + b/c

8 Computer Science Assuming the stack is initially empty, and using the standard PUSH and POP, what is the order of items on the stack (from top to bottom) when the following executes? X = 1 I = 1 REPEAT PUSH X X = X + 1 UNTIL (X > 8) WHILE (I <= 4) NUM1 = POP NUM2 = POP PUSH (NUM1 + NUM2) I = I + 1 ENDWHILE a. 3, 2, 1 b. 13, 8, 9, 1 c. 30, 3, 2, 1 d. 26, 4, 3, 2, A post-order traversal of the binary tree below would result in what numeric order? a. 1, 2, 3, 4, 5, 6 b. 1, 2, 4, 3, 5, 6 c. 4, 2, 1, 5, 3, 6 d. 4, 2, 5, 6, 3, The reverse Polish expression ABCDE+-*/ is equivalent to a. B * (C - (D + E)) / A b. A / B * (C - D + E) c. A / B * C - D + E d. A / (B * (C - (D + E)))

9 Computer Science What is the value of Y after the following executes? X = 0, Y = 0, Z = 64 WHILE (Z > 0) Y = Y + 2 Z = Z DIV 2 X = X + Y ENDWHILE a. 0 b. 14 c. 12 d What is the value of N after the following executes? B = 20, N = 0 FOR I FROM 1 TO 4 FOR J FROM 1 TO 4 ARR[I,J] = B ENDFOR B = B - 1 ENDFOR FOR J FROM 1 TO 4 N = N + ARR[J, 2] ENDFOR a. 74 b. 31 c. 19 d. 57

10 Computer Science What is returned for A after the function C call below? A = 0, X = 0 X = X + 8 A = C(X) FUNCTION C(X) IF (X <= 0) THEN RETURN (1) ELSE RETURN (C(X-1) + C(X - 3)) ENDIF ENDFUNCTION a. 28 b. 9 c. 41 d The reverse Polish expression AB*CD-+ is best represented by which binary expression tree below: + a. b. + A B * - * A B C D - C D c. B d. A A + * B * - C C - + D D

11 Computer Science What is the value of X after the C1 function calls execute? X = 0 X = C1(C1(X) + 2) FUNCTION C1(A) IF (A <= 0) THEN RETURN (0) ELSE RETURN (C1(A - 1) + 3) ENDIF ENDFUNCTION a. 1 b. 2 c. 0 d After the following executes, what values are stored in the array ARR[1..8]? FOR I FROM 1 TO 8 ARR[I] = I END FOR IF (ARR[7] < ARR[8]) THEN FOR J FROM 1 TO 4 ARR[J] = ARR[9 - J] ENDFOR ENDIF a. 1, 2, 3, 4, 5, 6, 7, 8 b. 8, 7, 6, 5, 4, 3, 2, 1 c. 8, 7, 6, 5, 5, 6, 7, 8 d. 1, 2, 3, 4, 4, 3, 2, 1

12 Computer Science After the function call executes, what is the value of Y? X = 10, Y = 0 Y = F1(X) FUNCTION F1(N) Y = 0 REPEAT IF (N MOD 2 = 1) THEN Y = Y + 1 ENDIF N = N DIV 2 UNTIL (N = 0) RETURN(Y) ENDFUNCTION a. 1 b. 2 c. 3 d How many nodes can a binary tree with 5 levels have? a. 5 b. 10 c. 31 d. 32

13 Computer Science What value is returned to Z after the call to F1? X = 6, Y = 3 Z = F1(X, Y) FUNCTION F1(X, Y) IF (X < Y) THEN RETURN (Y) ELSE RETURN (F1(X - 1, Y) + 1) ENDIF ENDFUNCTION a. 3 b. 9 c. 8 d If initially the array ARR[1..5] = 3, 2, 5, 1, 7, then, after the code executes, the values of ARR[1..5] will be what set of numbers? FOR I FROM 1 TO 4 IF (ARR[I] > ARR[I + 1]) THEN X = ARR[I + 1] ARR[I + 1] = ARR[I] ARR[I] = X ENDIF ENDFOR a. 3, 2, 5, 1, 7 b. 1, 2, 3, 5, 7 c. 2, 3, 1, 5, 7 d. 7, 5, 3, 2, 1 e. 3, 3, 5, 5, 7

14 Computer Science If arguments for both subprograms are passed by reference, what is the value of A after the code executes the subprogram calls? A = 4 SUBA(A) SUBB(A) SUBPROGRAM SUBA(N) N = N - 1 ENDSUBPROGRAM SUBPROGRAM SUBB(N) SUBA(N) N = N * 2 ENDSUBPROGRAM a. 4 b. 3 c. 2 d. 1

15 Computer Science What operation of the list of ITEMs does the following pseudocode indicate when X(HEAD) is executed? (HEAD is an ITEM with no data) type ITEM (list element) ITEM.DAT (item data) ITEM.NXT (pointer to next item) type PTR (pointer to ITEM) variables PTR:HEAD (start of list) PTR:P (pointer to ITEM) PTR:NIL (end, no NXT value) FUNCTION X (PTR:P) (returns integer) N = 0 WHILE (P.NXT NOT = NIL) P = P.NXT N = P.DAT P.DAT = 0 ENDWHILE RETURN X = N ENDFUNCTION a. finds the address of last ITEM b. counts ITEMs in list c. zeroes all data values in the list d. sets all ITEM data to NIL e. returns value (list size -1)