2006 AP CSA FRQ 1: DailySchedule
Topic: ArrayList & Object Interaction
Skills Tested: ArrayList traversal, object method calls, removing while iterating, boolean logic
Curriculum Alignment: Unit 4 (Data Collections) (2025-2026 AP CSA)
Points: 9 | Time Estimate: ~22 minutes
Study This Topic: Unit 4: Data Collections Complete Study Guide
Part (a)
Write the conflictsWith method that returns true if this appointment's time overlaps with another appointment's time.
Try It First! Attempt to solve this part before viewing the solution.
Solution
public boolean conflictsWith(Appointment other)
{
return getTime().overlapsWith(other.getTime());
}Part (b)
Write the clearConflicts method that removes all appointments from the schedule that conflict with the given appointment.
Solution
public void clearConflicts(Appointment appt)
{
int i = 0;
while (i < apptList.size())
{
Appointment listAppt = (Appointment) apptList.get(i);
if (appt.conflictsWith(listAppt))
apptList.remove(i);
else
i++;
}
}Part (c)
Write the addAppt method that adds an appointment to the schedule, clearing conflicts first if it's an emergency.
Solution
public boolean addAppt(Appointment appt, boolean emergency)
{
if (emergency)
{
clearConflicts(appt);
apptList.add(appt);
return true;
}
for (int i = 0; i < apptList.size(); i++)
{
Appointment listAppt = (Appointment) apptList.get(i);
if (appt.conflictsWith(listAppt))
return false;
}
apptList.add(appt);
return true;
}Key Concepts
✓ Use helper methods (conflictsWith) when they're provided
✓ While loop for removal prevents skipping elements
✓ Only increment index when NOT removing
✓ Check emergency flag first for early return pattern
Common Mistakes to Avoid
✗ Using for-each loop when removing causes ConcurrentModificationException
✗ Incrementing index after removal skips elements
✗ Not using the provided conflictsWith method
✗ Forgetting to add the appointment after clearing conflicts
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About the Author: Tanner Crow is a certified AP Computer Science teacher with 11+ years of experience.
Last updated: January 2026