Mr. Meinzen - Advanced Placement Computer Science - A

APCS-A Handout: Aptitude Questions

See which of these questions you can answer correctly...

Question #1

Given the following function definition:

public void fun(int n)       
{       
     if (n > 1) 

         fun( n/2 ); 

     System.out.print(n+" "); 
}        

The function call fun(16) will yield as output which of the following sequences of numbers?

A. 10 8 6 4 2
B. 16 8 4 2 1
C. 1 2 4 8 16
D. 32 16 8 4 2
E. 2 4 8 16 32

Question #2

If b is a boolean variable, then the statement b = (b == false) has what effect?

A. It causes a compile-time error message.
B. It causes a run-time error message.
C. It causes b to have value false regardless of its value just before the statement was executed.
D. It always changes the value of b.
E. It changes the value of b if and only if b had value true just before the statement was executed.

APCS-A Handout: Abstract Class Worksheet

Given the following two classes, write an abstract class with appropriate abstract & concrete methods/fields that incorporate necessary features of the two classes.

public class Wheels
{
	  private double radius = 1.0;
	  private int    width = 14;
  
	  public Wheels(double r) {radius = r;}
    
	  public Wheels(double r, int w) {
		  radius = r;
		  width  = w;
	  }
  
	  public double getArea() {
		  return 3.1415*radius*radius;
	  }
}
  
public class Rollers
{
	  private double radius   = 1.0;
	  private String description;
  
	  public Rollers(double r) {radius = r;}
  
	  public Rollers(double r, String d) {
		  radius       = r;
		  description  = d;
	  }
  
	  public double getArea() {
		  double width = 5;
		  return 2.0*3.1415*radius*width;
	  }
}

Write the abstract class RoundShape and the Wheel class using the following class headers:

       
public abstract class RoundShape
{
   ...
}
public class Wheel extends RoundShape
{	
   ...
} 

APCS-A Handout: Data Structures and JCF Modeling

Choose the Data Structure that most closely resembles the situation. Be as specific as possible since there may be more than one possible answer.

Possible answers for general data structure: queue, singly linked list, stack, array, tree, binary search tree, priority queue, list, set, map, matrix

Possible answers for Java Collections Framework (JCF): ArrayList, LinkedList, HashSet, HashMap, TreeSet, TreeMap, Collection

Now its your turn: Write an example like the above. Also, write the name of the data structure that your example models. Your answers should contain at least two complete sentences. You should also consider (and explain) other possible data structures that may be used along with your model that could be appropriate.

APCS-A Handout: Maps & Sets Modeling 

• Determine if, in a given situation,
• the data structure should be arranged as a Tree or a Hash table
• then determine if it should be organized as a Map or Set.
• Give Big-Oh time estimates for :
  1. inserting an element,
  2. retrieving an element and
  3. sorting
• Please note that, for any given scenario, more information may be needed to give a definitive answer. In other words, there may be several correct answers from the given information. Assume your teacher will give additional information based upon your questions/assumptions for each scenario.

• 	Scenario	Tree or Hash	Set or Map	O(insert)	O(get)	O(sort)
  1	A city may have several zip codes. Implement a group of cities with corresponding zip codes.
  2	A word may have several definitions. Implement a simple dictionary.
  3	Cars are to organized by date of manufacturing or VIN number.
  4	A function where the independant variable (i.e. x) is the number of units consumed and the dependant variable (i.e. y) is profit.
  5	A function where where the independant variable is an address and the dependant variable is name of a resident.
  6	A relation where Objects are stored in specific memory locations
  7	A dictionary where one word may have several definitions and one definition may apply to more than one word.
  8	A translator where an English word is translated to a single French word
  9	In order to keep statistics for football, every player has a record of their percentage of "effectiveness". What data structure(s)would you use to optimize the sorting of players by their "effective" percentage?

APCS-A Handout: Exam Preparation Scores using the Practice Workbook

Fill out the table with the scores (percentage) and number of problems completed each hour.