Computer Science Invitational Test S19A Notes

Computer Science Invitational Test S19A

Question 1: Binary Sum Calculation

Determine the sum of the binary numbers 11100111₂ and 10110001₂.

• Choices:
  A. 40810
  B. 6318
  C. 110011001₂

Question 2: Output of Code Snippet

Evaluate the output of the following line of code:

out.print (14/2.0+3);

Choices:
A. 19716
B. 10
C. 2
D. 2.0
E. 10.0
F. None of the above
G. 19

Question 3: Printed Output of Code Segment

The following code outputs:

out.println("Houston");
out.print ("San \nAntonio");

• Choices:
  A. Houston
  B. Houston San
  C. Houston San Antonio
  D. Houston San Antonio
  E. Error. Will not compile due to an invalid escape sequence.

Question 4: Substring Usage

Analyze the code:

String s1="Dallas", s2="El Paso";
String s3=s2.substring(0, 2)+s1+s2.substring(3);
out.print(s3);

• Output Choices:
  A. Dallas El Paso
  B. El PDallasaso
  C. El Dallas Paso
  D. DallasEl Paso
  E. ElDallas Paso

Question 5: Boolean Expression Output

Examine the following boolean expression:

boolean bl=true, b2=false, b3=false;
out.println(!bl&&b2&&!b3);

• Output Choices:
  A. true
  B. false

Question 6: Minimum Value Calculation

Consider the code:

double d1=8.36;
double d2=-15.01;
out.print (Math.min(d1, d2));

• Output Choices:
  A. -15.01
  B. 8.36
  C. -15.01 8.36
  D. 8.36 -15.01
  E. 8

Question 7: Division Output

Evaluate:

double d=4;
int i=8;
out.print(i/d);

• Output Choices:
  A. 0
  B. 2.0
  C. 2
  D. 4.0
  E. 12

Question 8: String Manipulation

Analyze the following code:

String str="Lollapalooza";
if(str.length() <=11)
out.print("A");
if (str.endsWith("ooza"))
out.print("B");
else if(str.charAt (1)=='0')
out.print("C");

• Output Choices:
  A. A
  B. B
  C. ABCD
  D. C
  E. AB
  F. AC

Question 9: Loop Output

Examine the loop:

int x=6;
while(x>0) {
  if (x==2)
out.print ("\n");
out.print("#");
x--;
}

• Output Choices:
  A. ###
  B. ##
  C. ####
  D. ######
  E. ####

Question 10: Array Modification Output

Analyze the following array operations:

String[] list= {"public", "class", "extends", "void", "int", "double"};
list [2]="boolean";
list [list.length-3]="static";
out.print (Arrays.toString(list));

• Output Choices:
  A. [public, class, boolean, extends, static, void, int, double]
  B. [public, boolean, extends, void, static, double]
  C. [public, class, extends, boolean, void, static, int, double]
  D. [public, class, boolean, static, int, double]
  E. [public, class, int, double, boolean, static]

Question 11: Error Identification in Code

Identify the line containing an error:

public class Q11 {
public static void main(String[] args) throws IOException {
  Scanner scan=new Scanner(new File("input.dat"));
  int sum=0, count=0;
  while (scan.hasNextInt()) {
  sum+=scan.nextInt();
  count++;
  }
out.print(count+" "+sum);
}
}

• Output Choices:
  A. line #1
  B. line #2
  C. line #3
  D. line #4
  E. None of the above. There are no errors in the code.

Question 12: Code Output Calculation

Analyze:

long x=5;
for (int y=3;y<15;y+=3)
  x+=y;
out.print(x);

• Output Choices:
  A. 45
  B. 30
  C. 35
  D. 50
  E. 32

Question 13: Operator Precedence

Identify which operator is applied last:

• Choices:
  A. &&
  B. ++
  C. !
  D. <=

Question 14: Short Data Type Limits

Determine which value cannot be stored in a short variable:

• Choices:
  A. -32768
  B. -32767
  C. 32768
  D. 32767
  E. None of the above. All values are valid.

Question 15: ArrayList Size Output

Evaluate:

ArrayList<Double> a=new ArrayList<Double>();
a.add(5.25); a.add(6.5); a.add(3.99);
a.add(4.75); a.add(1.0); a.add(0.5);
out.print (a.size());

• Output Choices:
  A. 5
  B. 6
  C. 4
  D. 3
  E. 0

Question 16: Code Segment Modification

Determine which can replace <code> in the class Pet:

public class Pet {
private String species;
private String name;
private double weight;
public Pet (String s, String n, double w) {
species = s;
name = n;
weight = W;
}
}

• Choices:
  A. implements
  B. extends
  C. super
  D. this
  E. double

Question 17: Super Constructor Call

Which constructor is called by super() in the first constructor?

• Choices:
  A. Util
  B. String
  C. System
  D. Pet
  E. Object

Question 18: Constructor Characteristics

The constructors in the Pet class are characterized as:

• Choices:
  A. overloaded
  B. overridden
  C. overwritten
  D. parallel

Question 19: Output of Pet Class Code

What is the output of the following client code?

Pet pet=new Pet("cat", "Felix");
out.println(pet);

• Output Choices:
  A. Felix cat null
  B. cat Felix
  C. Felix cat
  D. Felix cat 0.0
  E. There is no output due to an error.

Question 20: String Length Calculation

What does the following code output?

String s="fosterthepeople";
String[] sa=s.split("[eo]");
out.println(sa.length);

• Output Choices:
  A. 5
  B. 4
  C. 2
  D. 1
  E. 0

Question 21: Nested Array Output

Evaluate:

int[][] a = new int[3][];
int[] x = {1, 3, 5, 7};
int[] y = {8, 6, 4};
int[] z = {2, 3};
a[2]=x;
a[0]=y;
a[1]=z;
out.println(a[a[1][0]][a[2][1]]);

• Output Choices:
  A. 7
  B. 6
  C. 10
  D. There is no output due to an error.

Question 22: Method Return Value

Identify the output of the client code:

out.print(mtd(3, 6));
public static int mtd(int x, int n) {
 if (x==-n)
 return x;
 else
 return x+mtd(++x,n);
}

• Output Choices:
  A. 25
  B. 20
  C. 18
  D. 15
  E. 12

Question 23: HashSet Size Calculation

Determine the output of the following code:

Set<String> hs = new HashSet<String>();
hs.add("Dalhart");
hs.add("Borger");
hs.add("Silverton");
hs.add("Bovina");
hs.add("Borger");
hs.remove("Silverton");
out.print(hs.size());

• Output Choices:
  A. 3
  B. 4
  C. 5
  D. 2
  E. 0

Question 24: Scanner with Delimiters

Analyze the following code:

Scanner s = new Scanner("googlefacebookamazon");
s.useDelimiter("[aeiou]+);
int x = 0;
while (s.hasNext()) {
 s.next();
 x++;
}
out.print(x);

• Output Choices:
  A. 9
  B. 10
  C. 7
  D. 1
  E. 0

Question 25: Regular Expression Matcher

Evaluate the output of:

Pattern p = Pattern.compile("\\w?");
Matcher m = p.matcher("1");
out.print(m.matches());

• Output Choices:
  A. 0
  B. 1
  C. 49
  D. true
  E. false

Question 26: Iterator for List

What must replace <code> in the following code?

Iterator<String> i=<code>;
out.print(i.next());

• Options:
  A. iterator();
  B. iterator(list);
  C. Iterator.iterator();
  D. new Iterator();
  E. list.iterator();

Question 27: Output from Iterator Code

If <code> is correctly filled, what is the result of:

List<String> list = new LinkedList<String>();
list.add("list");
list.add("set");
out.print(i.next());

• Output Choices:
  A. list
  B. set
  C. map
  D. collection
  E. iterator

Question 28: Worst-case Time Complexity

What is the worst-case run time efficiency of the following code?

int n=10000;
while (n>0) {
 n/=2;
 out.println(n);  
}

• Time Complexity Choices:
  A. O(log n)
  B. O(n log n)
  C. O(n²)
  D. O(n)
  E. O(n³)

Question 29: String Comparison Output

What does this line print?

out.print("recursion".compareTo("recovery"));

• Output Choices:
  A. 567
  B. 0
  C. -1
  D. 1
  E. -1

Question 30: Random Number Generation Output

Which of the following may not be printed by the following code?

Random r = new Random();
out.print(r.nextInt(50));

• Output Choices:
  A. 0
  B. 1
  C. 50
  D. 51
  E. More than one of the above.

Question 31: Method Implementation

Which of the following must replace <code> in the search method?

public static int search (String[] list, String t) {
  for (int i=0;i<list.length; i++) {
    if (t.equals(list[i]))
      return <code>;
  }
  return -1;
}

• Options:
  A. list[i]
  B. list[i].length()
  C. list.length
  D. i
  E. t

Question 32: Type of Search Implemented

Assuming <code> is filled out correctly, which type of search does the search method implement?

• Choices:
  A. heap
  B. recursive
  C. binary
  D. sequential
  E. selection

Question 33: Time Complexity of Search Method

What is the worst-case run time efficiency of the search method?

• Efficiency Choices:
  A. O(1)
  B. O(n²)
  C. O(n)
  D. O(log n)
  E. O(n log n)

Question 34: String Conditional Output

Evaluate the following:

int moon=1;
String str="hello"+(moon>1?" goodbye " +moon+" yes ":" no "+moon+");
out.print(str);

• Output Choices:
  A. hello no 1 maybe
  B. hello goodbye 1 yes
  C. no 1 maybe
  D. goodbye 1 yes
  E. hello no maybe

Question 35: Replacement in Code Segment

Which cannot replace <code> in the given ArrayList segment?

ArrayList<Integer> list = new ArrayList<Integer>();
list.add(1); list.add(2);
for(<code> i:list)
out.println(i);

• Choices:
  A. int
  B. Integer
  C. double
  D. ArrayList
  E. More than one of the above.

Question 36: Data Structure Characteristics

Which of the following is true about the data structure diagrammed?

• Choices:
  A. It is a binary search tree.
  B. It is a max heap.
  C. It is a complete tree.
  D. It is a min heap.
  E. It is a complete graph.

Question 37: Boolean Expression Equivalence

Which Boolean expression is equivalent to the diagram?

• Choices:
  A. Ã * B⇒C
  B. A * B C
  C. A + B * C
  D. A + C + B
  E. A * B + C

Question 38: Graph Properties

Characterize the graph shown:

• Choices:
  A. undirected, weighted and complete
  B. directed, weighted and complete
  C. directed and unweighted
  D. connected, simple and complete
  E. directed and weighted

Question 39: Two's Complement Conversion

Write the binary 8-bit two's complement equivalent of 99 in the answer document.

Question 40: Infix Expression Conversion

Write the infix equivalent of the postfix expression AB+ CD * E/- in the answer document.