AP CSA FRQ Guide
2013 FRQ 3: GridWorldUtilities and JumpingCritter
Find empty locations in a grid and write a legacy critter that jumps to a random empty location or removes itself when none exists.
Legacy GridWorld List Processing22 minute targetGridWorldArrayList2D gridlegacy
Skills Tested
What this FRQ is really practicing
GridWorldArrayList2D gridlegacy
Treat these skills as the study checklist. If any tag feels shaky, review that topic before attempting the full written response.
Starter Approach
How to begin without copying a solution
- 1Part A: scan every valid grid location and collect empty ones.
- 2Part B: override the appropriate movement behavior to jump to a random empty location.
Write a first attempt before revealing any solution outline. Most AP CSA FRQ progress comes from tracing your own code and finding the missing case.
Common Mistakes
Mistakes to watch for while writing
Returning null for no empty locations.
Including occupied locations in the returned list.
Overriding act when the prompt says not to.
Self Check
Review questions before you submit
Creates and returns an ArrayList of empty locations.
Return an empty list, not null, when no locations are empty.
Traverses rows and columns in the grid.
Check each valid Location.
Checks whether each location is unoccupied.
Use grid.get(location) or equivalent GridWorld logic.
Chooses a random empty location for the jump.
Do not always choose the first empty location.
Practice Links