Problem Set 9

It's time to put your skills to the test. This problem set should look very familiar. It's the same thing as last time, except we're using lists instead of arrays.

Getting Started

To get started, create a GitHub repository to store your code. When you're finished, clone my skeleton to get all of the starter code and instructions. Setup a remote to push your code to your repository instead of mine.

Setup

1. Login to your GitHub account and create a new repository named pset-9.
2. In the terminal, navigate to your APCSA directory on the Desktop.

$ cd ~/Desktop/APCSA

3. Clone my skeleton repository into a directory named pset-9.

$ git clone git@github.com:ap-java-ucvts/pset-9-skeleton.git pset-9

4. Change into your newly created pset-9 directory.

$ cd pset-9

5. Overwrite the remote, which originally points at my skeleton repository.

$ git remote rename origin upstream

6. Add a new remote that points at your pset-9 repository. Replace YOUR-USERNAME with your actual username.

$ git remote add origin git@github.com:YOUR-USERNAME/pset-9.git

7. Open up the Exercises.java file, which is where you'll implement each of your solutions.

The first exercise is partially done for you (the input verification part, anyway). You'll be on your own for the rest. There are a lot of exercises in this problem set, but none of them are too challenging. Take your time and try not to get frustrated.

Exercises

The specifications for each exercise are outlined below. Your job is to write lines of code to solve the problems and return the desired values. Your code must meet the requirements set forth in this section. Each solution must be written in its own method, and named accordingly.

Work through these exercises on your own. Experiment, make mistakes, ask questions, and fix your mistakes. It's the only way to get good at programming.

While each of these exercises can be solved using loops and conditional statements, the built-in methods of the ArrayList class will surely make your lives much easier. Read the documentation and use these methods to help streamline your code!

Exercise 1 (commonEnd)

Given two ArrayLists of Integers, a and b, return true if the ArrayLists have either the same first element or the same last element. The ArrayLists must meed the following specifications, otherwise you should return false`.

• a and b must not be null
• a and b must have a size of at least 1

I've written the input verification portion of this exercise (i.e., the stuff that makes sure the above specifications are met). You'll need to finish the remainder of the exercise.

Use the provided grademe.sh script to verify your code against my test cases.

Exercise 2 (endsMeet)

Given an ArrayList of Strings, values, return a new ArrayList comprised of the first and last n elements of the original ArrayList. The input ArrayList must meet the following specifications, otherwise you should return an empty ArrayList.

• values must not be null
• values must have a size of at least n
• n must be a non-negative integer

Use the provided grademe.sh script to verify your code against my test cases.

Exercise 3 (difference)

Given an ArrayList of Integers, numbers, return the difference between the largest and smallest values. The input ArrayList must meet the following specifications, otherwise you should return -1.

• numbers must not be null
• numbers must have a size of at least 1

Use the provided grademe.sh script to verify your code against my test cases.

Exercise 4 (biggest)

Given an ArrayList of Doubles, numbers, return the largest value among the first, middle, and last elements in the ArrayList. The input ArrayList must meet the following specifications, otherwise you should return -1.

• numbers must not be null
• numbers must have an odd size of at least 3
• numbers must not contain any negative values

Use the provided grademe.sh script to verify your code against my test cases.

Exercise 5 (middle)

Given an ArrayList of Strings, words, return a new ArrayList comprised of the middle three elements of the original ArrayList. The input ArrayList must meet the following specifications, otherwise you should return an empty ArrayList.

• values must not be null
• values must not contain any null values
• values must have an odd size of at least 3

Use the provided grademe.sh script to verify your code against my test cases.

Exercise 6 (increasing)

Given an ArrayList of Integers, numbers, return true if there exists three consecutively increasing integers somewhere in the ArrayList. The input ArrayList must meet the following speciications, otherwise you should return false.

• numbers must not be null
• numbers must have a size of at least 3

Use the provided grademe.sh script to verify your code against my test cases.

Exercise 7 (everywhere)

Given an ArrayList of Integers, values, and a target int, x, return true if x is everywhere in the ArrayList. A target is defined as being everywhere if it is located adjacent to every other element. The input ArrayList and target must meet the following specifications, otherwise you should return false.

• values must not be null
• values must have a size of at least 1

Use the provided grademe.sh script to verify your code against my test cases.

Exercise 8 (consecutive)

Given an ArrayList of Integers, numbers, return true if the ArrayList contains three consecutive even or three consecutive odd numbers. The input ArrayList must meet the following specifications, otherwise you should return false.

• numbers must not be null
• numbers must have a size of at least 3

Use the provided grademe.sh script to verify your code against my test cases.

Exercise 9 (balance)

Given an ArrayList of Integers, numbers, return true if it is possible to split the ArrayList so that the sum of the left half is equal to the sum of the right half. The input ArrayList must meet the following specifications, otherwise you should return false.

• numbers must not be null
• numbers must have a size of at least 2

Use the provided grademe.sh script to verify your code against my test cases.

Exercise 10 (clumps)

Given an ArrayList of Strings, values, return the number of clumps in the ArrayList. A clump is defined as a consecutive series of two or more identical values. The input ArrayList must meet the following specifications, otherwise you should return -1.

• values must not be null
• values must not contain any null values

Use the provided grademe.sh script to verify your code against my test cases.

Tests

To test your code, use the provided grademe.sh script. To run the script, use the following command.

./grademe.sh exerciseName

It'll output the number passing test cases, as well as the input, expected output, and actual output of any failing test cases. Make sure your code is compiling before running this script, as it depends on the existence of a successfully compiling Exercises.java file.

Deadline

Please read very carefully. Historically, most students lose points on problem sets for simply failing to read the instructions and requirements.

• February 5, 2020, at 11:59pm.

If you submit your problem set at midnight (i.e., February 6, 2020, at 12:00am), it is considered late!

Submission Requirements

• Your code must compile. Code that fails to meet this minimum requirement will not be accepted.
• There must be at least 15 unique commits to your repository.
• Your code must meet each requirement outlined in the Exercises and Deliverables sections.
• Your code must adhere to the course style guidelines.

Happy coding!