Bengalensis Celandon Foundation Retake Exam

Getting Started

• Fork this repository under your own account
• Clone your forked repository to your computer
• Commit your progress frequently and with descriptive commit messages
• All your answers and solutions should go in this repository
• Follow the styleguide
• Take care of the naming of classes, fields, variables, files, etc.

Keep in mind

• You can use any resource online, but please work individually
• Don't just copy-paste your answers and solutions, use your own words instead
• Don't push your work to GitHub until your mentor announces that the time is up

Exercises

Multiply items in a matrix

Write a method that takes a matrix as a parameter.

The function should:

• multiply each odd number by 2 in every odd indexed row
• multiply each even number by 2 in every even indexed row

and then returns altered matrix. We are talking about indexing from developer's point of view (starting from 0). Zero is considered even number.

Write 2 different unit test cases for this function.

Example

Input

[
  [1, 3, 6, 2],
  [7, 5, 6, 1],
  [3, 3, 1, 5],
  [9, 0, 5, 3]
]

Returned matrix

[
  [1,  3,  12, 4],
  [14, 10, 6,  2],
  [3,  3,  1,  5],
  [18, 0,  10, 6]
]

Worst songs

Write a method worstYearInMusic(filename) which can read and parse a file containing information about world's worst songs. The method should receive one string parameter: the name of the file, and it should return the year in which the highest amount of these awful songs was created.

Possible file reading exceptions should be handled by printing error message to the terminal.

Example

Example input file can be found here.

Returned value for given file

1975

Hospital simulator

Now we are going to create a simple hospital simulator game. We will need patients, a hospital and different kinds of queues to handle our patients. You can implement the necessary classes in any order, but we suggest you to follow the order below.

Patient class

The Patient class doesn't depend on any other classes. It has twwo methods:

• getSeverity, that retrieves the severity of patient's sickness.
• treat, which decreases the severity of said sickness by 1. Even when treating repeatedly, the severity cannot go below 0!

When creating a new patient, his/her severity is set to a random number between 1 and 10.

Queue class

If you have Patients you can create an abstract Queue class. It will represent a way to hold the Patients waiting for treatment.

• It has queuePatientUp(patient) method that adds a Patient to the queue.
• It has an abstract method getNextPatient that returns next patient in the queue.

The implementation is up to you, you can store the patients in any data structure that seems suitable.

Hospital class

Since you have Queue class and Patients you can implement your Hospital class as well. The idea is that we are able to choose which kind of queue hospital is using when creating it. It should fulfill the following requirements:

• It has a Queue field, which content is set through Hospital's constructor parameter.
• It has addPatient(patient) method that adds a Patient to this hospital's queue.
• It has treatNextPatient method that treats the next patient in this hospital's queue.

ClassicQueue class

The classic queue is a specific queue type which is not abstract anymore. Its method getNextPatient has the following specification:

• It returns the next patient as they joined the queue (first patient to arrive is served first).
• When you return this patient, also remove him/her from the queue.
• Returns null if the queue is empty

SafeQueue class

The safe queue is a specific queue type which is not abstract anymore. Its method getNextPatient has the following specification:

• It always returns the patient with the highest severity.
• If there are more patients with the same severity you can return whichever.
• Returns null if the queue is empty

Command line exercise

Folder structure

• Take a look at this directory structure:

computer-shop
 |--desktop
 |   |--.git
 |   |--instock
 |   |   └--summary.csv
 |   └--in-transit
 |       └--summary.csv
 └--laptop
     |--.git
     |--transit-summary.csv
     |--in-stock
     |   └--summary.csv
     └--in-transit

• Your task is to write commands in the correct order based on tasks listed below.
• Your current directory is computer-shop/
• Take careful note of which folders are git repositories!

Your tasks

1. Rename desktop/instock/ folder to desktop/in-stock/
2. Move laptop/transit-summary.csv file into laptop/in-transit folder while renaming it to summary.csv
3. Delete the last 2 lines from laptop/in-stock/summary.csv
4. Add and commit all the changes in both repositories

Solution

cd desktop
mv instock in-stock
git add . 
git commit -m "changed the name of instock to in-stock"
cd
cd laptop
mv transit-summary.csv summary.csv
mv summary.csv in-transit/
head -n-2 in-stock/summary.csv
git add .
git commit -m "moved transit-summary.csv to summary.csv and moved it into in-transit/"