2026 Free Response

This question involves the Account class, which is used to represent user accounts for a website. The Account class contains a helper method, isAvailable, which determines whether a username is available. You will write a constructor and a method in the Account class.

public class Account
{
    private String username; // To be initialized in part (a)

    /**
     *  Creates a username based on the parameter requestedName. If the
     *  username is unavailable, appends successive integers, beginning
     *  with 1, to requestedName until an available username is found,
     *  as described in part (a).
     */
    public Account(String requestedName)
    { /* to be implemented in part (a) */ }

    /**
     *  Returns true if the parameter str is an available username;
     *  returns false otherwise.
     */
    public static boolean isAvailable(String str)
    { /* implementation not shown */ }

    /**
     *  Returns a shortened version of username with each hyphen ("-")
     *  and the character before it removed, as described in part (b)
     *  Preconditions: username does not start or end with a hyphen.
     *                 username does not contain consecutive hyphens.
     *                 username.length() >= 2
     *  Postcondition: username is unchanged.
     */
    public String getShortenedName()
    { /* to be implemented in part (b) */ }

    /* There may be instance variables, constructors, and methods
       that are not shown. */
}

The following information applies to part A.

In part A, you will write the Account constructor, which creates a username based on the parameter requestedName.

A helper method, isAvailable, has been provided to determine whether a username is available. The isAvailable method returns true if its parameter is an available username and returns false otherwise.

If requestedName is an available username, the Account constructor will assign requestedName to the instance variable username. If not, the constructor will try different variations of requestedName until an available username is found and assigned to the instance variable username. The variations consist of requestedName followed by an integer, as in the following example.

• If requestedName is "Luis-Cruz" and this username is not available, then the constructor will check the availability of "Luis-Cruz1", "Luis-Cruz2", "Luis-Cruz3", and so on, until an available username is found. The first available username found is assigned to username.
• If requestedName is "PSmith" and this username is available, then "PSmith" is assigned to username.

The following information applies to part B.

In part B, you will write the getShortenedName method, which returns a shortened version of the instance variable username with each hyphen ("-") and the character immediately before it removed. If no hyphens appear in username, the value of username is returned.

For example, if username is "Amy-Marie-Lin", getShortenedName should return "AmMariLin".

As another example, if username is "SammyB3", getShortenedName should return "SammyB3".

The Bottle class, which you will write, represents a bottle that contains liquid.

Bottle objects are created by calls to a constructor with a double parameter that represents the bottle's capacity, in milliliters (mL), which is the maximum amount of liquid in the bottle. Assume that this value will be greater than or equal to 0. When Bottle objects are constructed, each is filled to its capacity.

The Bottle class contains an updateAmount method, which updates the amount of liquid in the bottle. This method has a double parameter that represents the amount of liquid, in mL, to be removed from the bottle, with a precondition that the parameter is always greater than zero and less than or equal to the amount of liquid remaining in the bottle. If updating the amount of liquid in the bottle would cause it to be less than 25% of the capacity, the bottle is filled and reset to the capacity. The updateAmount method returns a double that represents the amount remaining in the bottle, in mL, after the amount has been updated.

The following table contains a sample code execution sequence and the corresponding results. The code execution sequence appears in a class other than Bottle.

Write the complete Bottle class. Your implementation must meet all specifications and conform to the examples shown in the table.

The CourseRecord class is used to store information about a student enrolled in a course. A partial definition of the CourseRecord class is shown.

public class CourseRecord
{
    /**
     *  Returns a unique ID for the student associated with this
     *  CourseRecord
     */
    public String getStudentID()
    { /* implementation not shown */ }

    /**
     *  Returns a nonnegative integer representing the number of times the
     *  student associated with this CourseRecord has been absent in the
     *  course
     */
    public int getAbsences()
    { /* implementation not shown */ }

    /* There may be instance variables, constructors, and methods
       that are not shown. */
}

The Attendance class maintains two ArrayLists of CourseRecord objects, named historyList and mathList. A partial definition of the Attendance class is shown.

public class Attendance
{
    /* The students enrolled in a history course */
    private ArrayList<CourseRecord> historyList;

    /* The students enrolled in a math course */
    private ArrayList<CourseRecord> mathList;

    /**
     *  Returns the number of students who are enrolled in both
     *  the history course and the math course but have more
     *  absences in the history course than the math course
     *  Preconditions:
     *          No student ID appears multiple times in historyList.
     *          No student ID appears multiple times in mathList.
     *          historyList and mathList do not contain any null elements.
     *  Postcondition:
     *          historyList and mathList are unchanged.
     */
    public int moreHistoryThanMathAbsences()
    { /* to be implemented */ }

    /* There may be instance variables, constructors, and methods
       that are not shown. */
}

Write the Attendance method moreHistoryThanMathAbsences. The method should return the number of students who are enrolled in both the history course and the math course but have more absences in the history course than the math course.

For example, suppose historyList and mathList have the following contents.

historyList:

mathList:

In this example, there are four student IDs ("dr03", "ot32", "sq98", and "ry00") that appear in both historyList and mathList. Of these, only "ot32" and "sq98" have more absences in the history course than the math course, so the moreHistoryThanMathAbsences method should return 2.

Complete method moreHistoryThanMathAbsences.

/**
 *  Returns the number of students who are enrolled in both
 *  the history course and the math course but have more
 *  absences in the history course than the math course
 *  Preconditions:
 *          No student ID appears multiple times in historyList.
 *          No student ID appears multiple times in mathList.
 *          historyList and mathList do not contain any null elements.
 *  Postcondition:
 *          historyList and mathList are unchanged.
 */
public int moreHistoryThanMathAbsences()

The Space class is used to represent the spaces on a game board. A partial definition of the Space class is shown.

public class Space
{
    /**
     *  Returns the color of the space
     */
    public String getColor()
    { /* implementation not shown */ }

    /**
     *  Returns the point value of the space
     */
    public int getPoints()
    { /* implementation not shown */ }

    /* There may be instance variables, constructors, and methods
       that are not shown. */
}

The GameBoard class maintains a two-dimensional array of Space objects that represents a game board. A partial definition of the GameBoard class is shown.

public class GameBoard
{
    private Space[][] board;

    /**
     *  Returns the point value of the row in board specified by the
     *  parameter. The point value is the sum of the points in the row,
     *  or two times the sum of the points in the row if all spaces in
     *  the row are the same color.
     *  Preconditions: No elements of board are null.
     *                 board has at least two rows and
     *                 at least two columns.
     *                 targetRow is a valid row index.
     */
    public int getPointsForRow(int targetRow)
    { /* to be implemented */ }

    /* There may be instance variables, constructors, and methods
       that are not shown. */
}

When an element of the two-dimensional array board is accessed, the first index is used to specify the row and the second index is used to specify the column.

Write the GameBoard method getPointsForRow. The method should return the point value of the spaces in the row specified by the parameter targetRow. The point value of a row is determined as follows.

• If not all spaces in the row are the same color, the point value for the row is the sum of the points in the row.
• If all spaces in the row are the same color, the point value for the row is two times the sum of the points in the row.

For example, suppose board has the following contents. For each element, the first value is the color and the second value is the point value.

For these contents of board, the expected behavior of getPointsForRow is as follows.

• The call getPointsForRow(0) should return 1300. Not all spaces in this row are the same color, so the sum of the points in the row is returned.
• The call getPointsForRow(2) should return 2000. The sum of the points in row 2 is 1000, and all spaces in this row are the same color, so two times this sum is returned.

Complete method getPointsForRow.

/**
 *  Returns the point value of the row in board specified by the
 *  parameter. The point value is the sum of the points in the row,
 *  or two times the sum of the points in the row if all spaces in
 *  the row are the same color.
 *  Preconditions: No elements of board are null.
 *                 board has at least two rows and
 *                 at least two columns.
 *                 targetRow is a valid row index.
 */
public int getPointsForRow(int targetRow)