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### 2019 AP CS Exam Free Response Solutions

## AP Computer Science Practice Problems & Resources by Topic

Each section focuses on an AP Computer Science Exam topic that has been tested extensively on previous exams.

All problems were created by AP CS Tutor Brandon Horn of mrHorn.com, Inc.

### Featured Practice Problems – Droppy & Mazer

- Traverse a 2D array in a non-trivial order (like the AP CS Pictures Lab)
- Manipulate String objects (like the AP CS Magpie Lab)

Try the Droppy Free Response Practice Problem

Try the Mazer Free Response Practice Problem

### Inheritance & Polymorphism

- Design and implement subclasses
- Override superclass methods
- Work with abstract classes and methods

See the Inheritance & Polymorphism Practice Problems

### 2D Arrays

- Traverse a 2D array in row-major order
- Fill a two dimensional array
- Visit specific elements of a 2 dimensional array

See the 2D Array Practice Problems

### Recursion

- Trace recursive methods
- Implement recursive methods
- Determine the purpose of recursive methods

See the Recursion Practice Problems

See the Recursive Method Tracing Technique

### Lists & ArrayLists

- Compare consecutive elements of a List
- Remove specific elements from a List
- Find the maximum in an ArrayList

See the List & ArrayList Practice Problems

### Sorting & Searching

- Code selection sort, insertion sort and merge sort
- Identify and complete variants (ex: back to front)
- Determine if an implementation is correct

Try the Sorting & Searching Practice Problems

### GridWorld: The AP Computer Science Case Study

Note: GridWorld will not be featured on the 2015 and subsequent AP CS Exams.

- Practice with Location and Grid
- Write a complete subclass of Critter
- Use Grid to implement a game

See the GridWorld Case Study Practice Problems

See the GridWorld Case Study Explanations

See the GridWorld Case Study Solutions

### Additional Practice Problems by Topic

## Solutions to AP Computer Science Exam Problems

### Multiple Choice Solutions for Released Exams

- 2004 AP CS A Multiple Choice Explanations
- A level from 2004 AP CS AB Multiple Choice Explanations
- 2009 AP CS A Multiple Choice Explanations

### 2019 AP CS Exam Free Response Solutions

- APCalendar Free Response Solution
- StepTracker Free Response Solution
- Delimiters Free Response Solution
- LightBoard Free Response Solution

### 2018 AP CS Exam Free Response Solutions

- FrogSimulation Free Response Solution
- WordPairList Free Response Solution
- CodeWordChecker Free Response Solution
- ArrayTester Free Response Solution

### 2017 AP CS Exam Free Response Solutions

- Digits Free Response Solution
- MultPractice Free Response Solution
- Phrase Free Response Solution
- Successors Free Response Solution

### 2016 AP CS Exam Free Response Solutions

- RandomStringChooser Free Response Solution
- LogMessage Free Response Solution
- Crossword Free Response Solution
- StringFormatter Free Response Solution

### 2015 AP CS Exam Free Response Solutions

### 2014 AP CS Exam Free Response Solutions

- scrambleWord and scrambleOrRemove free response solution
- Director free response solution
- SeatingChart free response solution
- Trio free response solution

### 2013 AP CS Exam Free Response Solutions

- MusicDownloads Free Response Solution
- TokenPass Free Response Solution
- GridWorldUtilities & JumpingCritter Free Response Solution
- Skyview Free Response Solution

### 2012 AP CS Exam Free Response Solutions

- ClimbingClub Free Response Solution
- RetroBug Free Response Solution
- HorseBarn Free Response Solution
- GrayImage Free Response Solution

### 2011 AP CS Exam Free Response Solutions

- Sound Free Response Solution
- AttractiveCritter Free Response Solution
- FuelDepot Free Response Solution
- RouteCipher Free Response Solution

### 2010 AP CS Exam Free Response Solutions

- MasterOrder Free Response Solution
- APLine Free Response Solution
- Trail Free Response Solution
- GridChecker Free Response Solution