TRIAL EXAM: Programming Basics

Getting Started

• Fork this repository under your own account
• Clone the forked repository to your computer
• Commit your progress frequently and with descriptive commit messages
• All your answers and solutions must go in this repository
• Please create directories for each of the tasks except the question time
• Don't forget to answer the questions

What can I use?

• 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

Tasks

Symmetric matrix

Create a function named isSymmetric that takes an n×n integer matrix (two dimensional array/list) as a parameter and returns true if the matrix is symmetric or false if it is not.

Symmetric means it has identical values along its diagonal axis from top-left to bottom-right, as in the first example.

Example 1:

[
  [1, 0, 1],
  [0, 2, 2],
  [1, 2, 5]
]

Output:

true

Example 2:

[
  [7, 7, 7],
  [6, 5, 7],
  [1, 2, 1]
]

Output:

false

Most Common Characters

Write a function that takes a filename as a parameter. Return the 2 most common characters and their occurrences in the file's content.

If the file does not exist throw an exception with the following message: "File does not exist!"

Example

Example file can be found here

Output

{
  "e": 6,
  "l": 4
}

Pirates

Write a program which can store pirates in a ship.

Pirate

• A pirate has a name, an amount of gold and health points, the default value of which is 10.

• A pirate might be a captain and may have a wooden leg.

• You must create the following methods:

• if a pirate is a captain:

  • work() which increases the amount of gold possessed by that pirate by 10 and decrease the HP by 5.
  • party() which increases the HP by 10.

• if the pirate is not a captain:

  • work() which increases the amount of gold by 1 and decreases the HP by 1.
  • party() which increases the HP by 1.

• toString() method:

• if the pirate has a wooden leg, then the string that is returned by the function must look like this:

  • Hello, I'm Jack. I have a wooden leg and 20 golds.

• If not:

  • Hello, I'm Jack. I still have my real legs and 20 golds.

Ship

• It should have a list of pirates.
• You must be able to add new pirates to the ship. It must have only one captain!
• You must create the following methods:
• getPoorPirates() which returns a list of names containing the pirates that
  • have a wooden leg and have less than 15 golds
• getGolds() which returns the sum of gold owned by the pirates of that particular ship
• lastDayOnTheShip() which calls the pirates' party() method.
• prepareForBattle() which calls
  • the pirates' work() method 5 times
  • then the ship's lastDayOnTheShip() method.

Question time!

How can you generate a random number?

In JS we can generate a random number on the [0, 1) set with Math.random(). Then we can scale it with arithmetic operations ('*', '+', '-' etc.) and we can use Math.floor(), .round() or .ceil() if we need integers only.

What is a ternary operator? How does it work?

The ternary operator is kind of a shorthand for an if statement in JS.

Syntax: 'condition' ? 'result if condition is met' : 'result if condition is not met'