AP Computer Science A Prep, 2024 - Rob Franek 2023
2 How to Approach Multiple-Choice Questions
Part IV: Test-Taking Strategies for the AP Computer Science A Exam
FREE-RESPONSE STRATEGIES
Write Java Code, Not Pseudocode
Only Java code is graded; pseudocode is not graded. Don’t waste time writing pseudocode if you don’t know how to code the solution to a problem. (On the other hand, write pseudocode as a starting point to writing your Java code if it helps you to do so.)
Don’t Comment on Your Code
Unless you write some code that is extremely tricky (and see below for whether or not you should do that!), there’s no need to write comments. It just takes time (that you don’t have a lot of), and the comments will be largely ignored by the graders anyway (you won’t get points if your comment is correct but your code is wrong). You also run the risk of misleading the grader if your code is correct but your comments are incorrect.
Write Legibly
This seems obvious, but if a grader can’t read your code, you won’t get any points.
Don’t Erase Large Chunks of Code
If you make extensive changes to the code you’re writing, it’s better to put a big “X” through the bad code rather than erase it. It saves you time and makes it easier for the graders to read.
Don’t Write More Than One Solution to a Problem
Graders will grade the first solution they see. If you rewrite a solution, be sure to cross out the old one.
Don’t Leave any Problem Blank
You don’t get any points if you don’t write anything down. Even if you’re unsure how to answer a particular problem (or part of a problem), analyze the problem and code the method’s “infrastructure.”
For instance, if the method signature indicates that it creates and returns an ArrayList, writing
ArrayList returnedList = new ArrayList();
return returnedList;
is likely to get you at least partial credit—even if you don’t know how to fill the ArrayList with the correct objects.
KISS (Keep It Simple, Student)
The free-response problems are designed to make the solutions relatively straightforward. If your solution is getting complicated, there’s probably an easier or better way to solve the problem. At the same time, don’t try for seemingly elegant but unreadable code. Remember that graders must read hundreds of exams in a week—they may not have time to figure out all of the nuances of your code. KEEP IT SIMPLE!
Write Standard Solutions
Use AP-style variable, class, and method names and follow the indentation style of the AP sample code (even if you don’t like their style!). Although graders always try to be fair and accurate, they are human and do make mistakes. The closer your answer adheres to the sample solution given to the graders, the easier it will be for them to grade.
Wherever possible, use clear and intuitive nomenclature. For example, use r and c or row and col for looping through the rows and columns of a two-dimensional array, don’t use x and y or a and b or jack and jill. This ensures that graders can easily follow the flow of your code.
If the Pseudocode for an Algorithm Is Given, Use it!
Sometimes you will have to create your own algorithm for a method. Often, though, the pseudocode for the algorithm or method is given to you as part of the problem; all you need to do is implement the algorithm. In that case, use the pseudocode that’s given to you! Don’t make it harder on yourself by trying to re-create the algorithm or implement your own special version. Furthermore, you can often write the code for a method based on given pseudocode even if you don’t understand the underlying algorithm.
Answer Part (c) to a Problem Even If You Can’t Do Parts (a) and (b)
Many parts of free-response problems build on previous parts. For example, the question in part (c) may use the methods you wrote in parts (a) and (b). However, you do not need to have answered parts (a) and (b) correctly in order to get full credit for part (c). In fact, part (c) is sometimes easier than either part (a) or (b). If part (c) states that you should use parts (a) and (b), use them!
Don’t Make Easy-to-Avoid Mistakes
Students often lose points on the free-response section because they make common errors. Here are some things you can do to avoid these mistakes.
· Unless the problem explicitly asks you to output something (using System.out.print), never output anything in a method you write.
· Watch method signatures. Be sure to call a method with the correct name and correct number and type of parameters. If the method is not void, be sure that the method you write returns a value with the correct type as specified in the signature.
· Use the objectName.methodName() syntax when calling methods of a given object; use the ClassName.methodName() syntax when calling static methods such as the random method of the Math class.
· Be sure to declare any variables you use (and give them descriptive names).
· Don’t create objects when you don’t need to. For instance, if a method you call returns an ArrayList, declare it as
ArrayList returnedList;
returnedList = obj.getList();
and
ArrayList returnedList = new ArrayList();
returnedList = obj.getList();
· Use proper indentation. Even if you use curly brackets for all of your conditionals and loops, the indentation will demonstrate your intent should you forget, for example, a closing curly brace.
Design Question
One problem in the free-response section is likely to be a design problem for which you will be given a description of a class and asked to write an interface (code) for it. You may also be asked to implement selected methods in your class. Be sure to use appropriate class, method, and private data field names. For example, “method1” is not likely to be a good name for a method that returns the total price of an object; “totalPrice” is a more appropriate name. Be sure to include all methods, private data fields, and all of the constructors (including the default constructor) asked for in the problem. If you are asked to implement a method, be sure to use the correct class, method, and private data field names as you defined them in the design part.
Arrays and ArrayLists
At least one problem (probably more) on the exam is likely to involve walking through arrays and/or ArrayLists. Know the differences between the two types of structures and how to loop through elements in an array or an ArrayList. Know how to use iterators and how to work with two-dimensional arrays.
GENERAL STRATEGIES
The following strategies apply to both the multiple-choice and free-response sections of the exam.
Write in the Test Booklet
Don’t try to do the questions in your head. Write things down! Take notes on the question. In addition to making the problem easier to solve, having notes in the test booklet will make it easier to go back and check your work if you have time at the end of the test.
Underline Key Words in Questions
Words like client program, sorted, ordered, constant, positive, never, always, and must all specify conditions to a problem. On both the multiple-choice and free-response sections, underline these key words as you read each question to reinforce their importance to the problem.
Don’t Do More Work Than You Need To
You are not graded for your work at all on the multiple-choice section, and you are not given extra credit for clever or well-documented answers on the free-response section. Keep it simple and strive to get the answer right rather than impress the graders.
Look Through the Exam First—Use the Two-Pass System
Keep in mind that all of the multiple-choice questions are worth the same number of points, and each free-response question is worth the same number of points as the other free-response questions. There is no need to do them in order. Instead, use a two-pass system.
Go through each section twice. The first time, do all the questions that you can get answers to immediately—that is, the questions with little or no analysis or the questions on computer science topics in which you are well-versed.
On the first round, skip the questions in the topics that make you uncomfortable. Also, you might want to skip the ones that look like number crunchers (you might still be expected to crunch a few numbers—even without a calculator). Circle the questions that you skip in your test booklet so you can find them easily during the second pass.
Once you’ve done all the questions that come easily to you, go back and pick out the tough ones that you have the best shot at.
That’s why the two-pass system is so handy. By using it, you make sure that you get to see all the questions that you can get right, instead of running out of time because you got bogged down on questions you couldn’t do earlier in the test.
A word of caution though: if you skip a multiple-choice question, be sure that you take extra care in marking your answer sheet. Always be sure that the answer you bubble in on the answer sheet is for the correct question number. In addition, don’t forget to circle the skipped question in the multiple-choice booklet so that you remember to come back to it if you have time at the end of the test.
Pace Yourself and Keep Track of Time
On the multiple-choice section, you should take an average of 2 minutes per problem. This will give you 3 minutes to look over the test at the beginning and 7 minutes for a final check at the end. As a comparison, if you take 3 minutes per problem, you’re going to answer only 30 questions; if you take 5 minutes per problem, you’re going to answer only 18 questions. Bear in mind, however, that 2 minutes per question is an average. Some questions will not require this much time, so it’s okay if a few questions take you longer than 2 minutes. After the first pass, reevaluate your pacing goal based on the number of questions and the amount of time you have remaining.
Looking For More Help with Your APs?
We now offer specialized AP tutoring and course packages that guarantee a 4 or 5 on the AP. To see which courses are offered and available, visit www.princetonreview.com/college/ap-test-prep
On the free-response section, you should pace yourself at a rate of 20 minutes per complete problem. This will give you roughly 2 minutes per problem to check your answer and a minute at the beginning to look over the problem.
Finally…
Don’t panic. If you’ve prepared, the test is easier than it looks at first glance. Take your time, approach each question calmly and logically, remember the tips in this chapter, and you’ll be fine.
Get Ready to Move On…
Now that you have the hints, strategies, and background information locked in, it’s time to move on to the serious business at hand…the content review (Part V). Read over the following chapters, take notes, and compare them to your textbook and class notes as preparation to take Practice Test 2 in the back of this book, and then Practice Test 3 (even farther into the back of the book) and Practice Tests 4 and 5 (found online). Once you’ve mastered what’s in this book and learned from your mistakes on the practice tests, you’ll be ready to ace the real AP Exam.
REFLECT
Think about what you have learned in Part IV, and respond to the following questions:
· How much time will you spend on multiple-choice questions?
· How will you change your approach to multiple-choice questions?
· What is your multiple-choice guessing strategy?
· How much time will you spend on free-response questions?
· How will you change your approach to the free-response questions?
· Will you seek further help, outside of this book (such as from a teacher, tutor, or AP Students), on how to approach multiple-choice questions, free-response questions, or a pacing strategy?