This repo contains an IntelliJ project for the 2020 S2 exam.

You have 3 hours and 15 mins to complete the exam.

This exam is open book. This means that you may use books, notes, and any other such pre-existing information as you complete the exam.

You must not communicate with any person other than the examiners at any time during the exam.

Chat, text, email and all other such forms of communications must be turned off prior to the exam and must remain off for the duration of the exam. The penalties for cheating in an exam at ANU are severe.

Important notes:

• There are six (6) questions, each worth different marks.
• The total marks for the exam are 90 (15 + 5 + 25 + 20 + 5 + 20)
• The exam will be entirely auto-graded, so it is important that your code passes the tests, and that you commit and push your work.
• The CI for the multiple choice question will not tell you whether your answer is correct, it will only tell you if your answer is formatted correctly.
• There are two practice questions, P1 and P2. You do not need to complete them. They are worth zero marks. They are there only to help you prepare your environment for the exam.

Using the incomplete template for Q1Floor.java, complete the unimplemented method findGreater().

Use the tests provided to test your solution, and then commit and push your changes to GitLab.

Using the incomplete template for Q1TwoThree.java, complete the unimplemented method twothree().

Use the tests provided to test your solution, and then commit and push your changes to GitLab.

Using the incomplete template for Q1Word.java, complete the unimplemented method find().

Use the tests provided to test your solution, and then commit and push your changes to GitLab.

Using the incomplete template for Q2Checksum.java, complete the unimplemented method checksum().

Use the tests provided to test your solution, and then commit and push your changes to GitLab.

Using the incomplete template for Q3Hollywood.java, complete all unimplemented methods.

You must complete your solution as a single file, Q3Hollywood.java. You are encouraged to create additional classes as required to solve the problem; any additional classes must be implemented as nested classes within the Q3Hollywood class.

Use the tests provided to test your solution, and then commit and push your changes to GitLab.

Using the incomplete template for Q3GetMaxCoStarsTest.java, write one or more unit tests for the getMaxCoStars() method. You must complete your solution as a single file, Q3GetMaxCoStarsTest.java. When writing the tests, you may assume that the provided methods in the Q3Hollywood class are correctly implemented.

The specification of the getMaxCoStars() method is provided in the Javadoc comment immediately above the method. This question is auto-graded; your tests will be run against multiple implementations of the getMaxCoStars() method, one of which is correct and some incorrect. Your test must be able to pass the correct implementation. If you cannot pass the correct implementation you will get zero (regardless of how many incorrect implementations you fail. If you pass the correct implementation, you will get one mark, and then one additional mark for each incorrect implementation that you fail.

Once you have completed your tests, commit and push your changes to GitLab.

Using the incomplete template for Q4FerrisWheel.java, complete each of the unimplemented methods.

Your solution must implement the data structure from first principles (as was done in lectures), avoiding use of Java's collection classes such as java.util.List. Solutions that ignore this requirement will be penalized accordingly.

Use the tests provided to test your solution, and then commit and push your changes to GitLab.

Using the incomplete template for Q5Address.java, complete the unimplemented methods hash() and equals(). You must implement hash() without using Java's built-in hashCode() method.

Use the tests provided to test your solution, and then commit and push your changes to GitLab.

For each of the following multiple-choice questions, identify the choice that provides the best answer. Record your choices in the file q-6.csv, one line per question.

For example, to answer "a" to question Q6.1, "d" to question Q6.2, "a" to question Q6.4, and leave question Q6.3 unanswered, you would record the following in q-6.csv:

1,a
2,d
4,a

Please note that you can only provide one answer to any multiple choice question. Please chose the answer that you think is the best answer. If you are unsure, leave it out, as in the example above where question 3 is left out.

Each question that is correctly answered gains you 5 marks, each question answered incorrectly loses you 1 mark, a question left unanswered neither loses nor gains marks. The final mark for the question is calculated by bounding the sum of marks between 0 and 20. For example, if you answered all questions correctly in the exam you would gain 20. If you answer 1 correctly and 2 incorrectly you would gain 3/20.

The exam CI will check whether your answer is correctly formatted. Note that the CI won't tell you whether your answer is correct. After you finish your questions you should commit your q-6.csv file and push it to the server. You should check the CI for any error messages relating to Q6 and fix them if they exist.

Given the following Java class:

public class Thready implements Runnable {
    int x = 1;
    int y = 1;

    public void run() {
        if (x == 2) x = 0;
        else incX();
        if (y == 2) y = 0;
        else y++;
    }

    public synchronized void incX() {
        x = x + 1;
    }
}

If two separate threads are created for the same instance of Thready, which of the following combinations of values for the fields x and y are not possible after both threads have run to completion?

a) x = 0, y = 3

b) x = 2, y = 2

c) x = 3, y = 0

d) x = 0, y = 2

e) x = 0, y = 0

This question relates to the following small JavaFX program:

public void start(Stage stage) throws Exception {
    stage.setTitle("Square");
    Group root = new Group();
    Scene scene = new Scene(root, 300, 300);
    stage.setScene(scene);
    Rectangle r = new Rectangle(100, 100, 100, 100);
    r.setFill(Color.RED);

    stage.show();
}

Select the option below which best describes the behavior of the program above:

a) It shows a window titled "Square" containing a red square within a white square.

b) It shows a window titled "Stage" containing a white square.

c) It shows a window titled "Square" containing a white square.

d) It does nothing.

Consider the method f() below.

static <T extends Comparable<T>> void f(List<T> in) {
    boolean s;
    do {
        s = false;
        for (var i = 1; i < in.size() - 1; i += 2) {
            if (in.get(i).compareTo(in.get(i + 1)) > 0) {
                var temp = in.get(i);
                in.set(i, in.get(i + 1));
                in.set(i + 1, temp);
                s = true;
            }
        }
        for (var i = 0; i < in.size() - 1; i += 2) {
            if (in.get(i).compareTo(in.get(i + 1)) > 0) {
                var temp = in.get(i);
                in.set(i, in.get(i + 1));
                in.set(i + 1, temp);
                s = true;
            }
        }
    } while (s);
}

Assuming in.get() is O(1), which of the following statements is correct?

a) The best-case time complexity of f() with in of size n is O(n).

b) The worst-case time complexity of f() with in of size n is O(n log n).

c) The worst-case time complexity of f() with in of size n is O(2 n).

d) The best-case time complexity of f() with in of size n is O(n^2).

This question relates to sentences (statements) in a language defined by a simple EBNF grammar. For reference, some symbols of EBNF are as follows:

= defines a production rule
, concatenation
| alternation / choice
[...] optional - zero or one
{...} optional - zero or more
(...) grouping
- exception
; terminates a production rule.

Given the following EBNF grammars, identify the one that best defines a grammar for accepting palindromes of the alphabet a, b, c, d (e.g. aa, abba, cadac, babcdcbab, etc). Note: a palindrome is a word that reads the same backwards and forwards.

a)

pal = 'a' | 'b' | 'c' | ... | 'x' | 'y' | 'z';

b)

alph = 'a' | 'b' | 'c' | 'd';
pal = alph | ('a', [alph], 'a') | ('b', [alph], 'b') | ('c', [alph], 'c') | ('d', [alph], 'd') | seq
seq = alph, {pal}, alph;

c)

alph = 'a' | 'b' | 'c' | 'd';
pal = alph | ('a', [pal], 'a') | ('b', [pal], 'b') | ('c', [pal], 'c') | ('d', [pal], 'd');

d)

alph = 'a' | 'b' | 'c' | ... | 'x' | 'y' | 'z';
seq = { 'alph' };
pal = seq, seq;

This is the end of the exam. What follows are instructions for the practice questions.

These are instructions for what to do before the exam.

You should do the two practice questions below, and ensure that they work in your environment. You should check:

1. that the provided test for P1 works correctly in IntelliJ,
2. that you can successfully pass the test for P1,
3. that you can fill in the answers for P2,
4. that you can can commit and push your work,
5. that the CI says that you have passed P1 and that P2 has been checked

Note that the CI will not tell you whether the multiple choice question P2 is correct or incorrect, it will only tell you whether it was correctly formatted.

Remember, the questions below are practice questions which you should attempt during the practice before the exam. The practice questions are here only to help you check that your environment is working correctly. The practice questions are not worth any marks.

The first is an example of a programming question.

Using the incomplete template for P1HelloWorld.java, complete the unimplemented main method.

Use the tests provided to test your solution, and then commit and push your changes to GitLab.

For each of the following multiple-choice questions, identify the choice that provides the best answer. Record your choices in the file p-2.csv, one line per question.

For example, to answer "a" to question P2.1, "d" to question P2.2, "a" to question P2.4, and leave question P2.3 blank, you would record the following in p-2.csv:

1,a
2,d
4,a

These practice questions are worth zero marks. But in the actual exam, there will be four multiple choice questions, and each question that is correctly answered gains you 5 marks, each question answered incorrectly loses you 1 mark, a question left unanswered neither loses nor gains marks. The final mark for the question in the exam is calculated by bounding the sum of marks between 0 and 20. For example, if you answered all questions correctly in the exam you would gain 20. If you answer 1 correctly and 2 incorrectly you would gain 3/20.

Once you have answered the questions you should commit your p-2.csv file, and push it. You should check the exam CI to see whether it passed the formatting check. If it did not, you should read the error messages and fix up any formatting problems with your answer. Note that the CI won't tell you whether your answers are correct, only whether they are correctly formatted.

Identify which of the following colors best represents the color of the sky:

a) blue

b) green

c) pink

d) purple

e) yellow

Identify which of the following numbers best represents the result of the addition 2 + 2:

a) 3

b) 2

c) 4

d) 5

e) 1

Identify which of the following animals is best associated with Australia:

a) tiger

b) elephant

c) kangaroo

d) lion

e) bear

Identify which of the following brands is best known as a car manufacturer:

a) Microsoft

b) Qantas

c) Toyota

d) Coca Cola

e) Facebook