C++ Online Test

A megastore offers three types of discounts, which are represented as DiscountType enum.

Implement the getDiscountedPrice method which should take the total weight of the shopping cart, the total price, and the discount type. It should return the final discounted price based on the discount schemes as shown in the promotional video below:

(Open full-size video in a new tab)

For example, the following code:

std::cout << MegaStore::getDiscountedPrice(12, 100, MegaStore::DiscountType::Weight);

should print:

82.0

A turn-based strategy game has a grid with water and land. The grid contains a true value where it's water and false where it's land.

The player controls a boat unit with a particular movement pattern. It can only move to fixed destinations from its current position as shown in the video below:

The boat can only move in a direct path through water to the possible destinations, so a destination will become unreachable if there is land in the way.

Implement the canTravelTo function, that checks whether a destination is reachable by the boat. It should return true for destinations that are reachable according to the pattern above, and false for unreachable or out of bounds destinations which are outside the grid.

For example, consider the following code:

vector<vector<bool>> gameMatrix = {
    {false, true,  true,  false, false, false},
    {true,  true,  true,  false, false, false},
    {true,  true,  true,  true,  true,  true},
    {false, true,  true,  false, true,  true},
    {false, true,  true,  true,  false, true},
    {false, false, false, false, false, false},
};

cout << canTravelTo(gameMatrix, 3, 2, 2, 2) << endl; // true, Valid move
cout << canTravelTo(gameMatrix, 3, 2, 3, 4) << endl; // false, Can't travel through land
cout << canTravelTo(gameMatrix, 3, 2, 6, 2) << endl; // false, Out of bounds

The following image shows valid and invalid destinations when the boat is in the position (3, 2):

A gaming company is working on a platformer game. They need a method that will compute the character's final speed, given a map and a starting speed.

The terrain on which the game character moves forward is made from various pieces of land placed together. Implement the method calculateFinalSpeed which takes the initial speed of the character, and an array of degrees of inclination that represent the uneven terrain.

The speed of the character will increase or decrease proportionally to the incline of the land, as shown in the image below:

The magnitude of the angle of inclination will always be < 90°. The speed change occurs only once for each piece of land. The method should immediately return 0 as the final speed if an incline reduces the speed to 0 or below 0, which makes the character lose 1 life.

For example, the below code:

std::cout << GamePlatform::calculateFinalSpeed(60.0, { 0, 30, 0, -45, 0 });

should print:

75

A playlist is considered a repeating playlist if any of the songs contain a pointer to a previous song in the playlist. Otherwise, the playlist will end with the last song which points to NULL.

Implement a function isInRepeatingPlaylist that, efficiently with respect to time used, returns true if a playlist is repeating or false if it is not.

For example, the following code prints "true" as both songs point to each other.

Song* first = new Song("Hello");
Song* second = new Song("Eye of the tiger");
    
first->next(second);
second->next(first);

std::cout << std::boolalpha << first->isInRepeatingPlaylist();

As part of a data processing pipeline, complete the implementation of the makePipeline method:

• The makePipeline method should accept a vector of functions, and it should return a new function that accepts one parameter arg.
• The returned function should call the first function in makePipeline with the parameter arg, and call the second function with the result of the first function.
• The returned function should continue calling each function in makePipeline in order, following the same pattern, and return the value from the last function.

For example,

std::vector<std::function<int (int)>> functions;
functions.push_back([] (int x) -> int { return x * 3; });
functions.push_back([] (int x) -> int { return x + 1; });
functions.push_back([] (int x) -> int { return x / 2; });
std::function<int (int)> func = makePipeline(functions);

and then calling func(3) should return 5.

Implement function countNumbers that accepts a sorted vector of unique integers and, efficiently with respect to time used, counts the number of vector elements that are less than the parameter lessThan.

For example, for vector v containing { 1, 3, 5, 7 }, countNumbers(v, 4) should return 2 because there are two vector elements less than 4.

Multiple choice test has several multiple choice questions. Each question can have only one correct answer. Additionally, timed multiple choice test can specify the time allowed for solving each question in the test.

The code below satisfies this specification, but the customer complained that the memory usage of the program constantly increases. Fix this problem.

User interface contains two types of user input controls: TextInput, which accepts all characters and NumericInput, which accepts only digits.

Implement the following methods:

• add on class TextInput - adds the given character to the current value
• getValue on class TextInput - returns the current value
• add on class NumericInput - overrides the base class method so that each non-numeric character is ignored

For example, the following code should output "10":

TextInput* input = new NumericInput();
input->add('1');
input->add('a');
input->add('0');
std::cout << input->getValue();

The C++ function getAppSettings returns the config settings for the app. The code below shows the main method using it:

#include <iostream>
#include <map>
#include <string>
#include <any>

std::any getAppSettings(bool detailed)
{
    if (detailed)
    {
        return std::map<std::string, std::string>
        {
            {"os", "Windows"},
            {"machine", "Workbook Pro"},
            {"user", "John93"}
        };
    }
    return std::string("Workbook Pro"); 
}

int main()
{
    std::any appSettings = getAppSettings(false);

    auto dict = std::any_cast<std::map<std::string, std::string>>(appSettings);
    std::cout << dict["os"] << std::endl;

    return 0;
}

The code in the main function causes the following runtime error.

terminate called after throwing an instance of 'std::bad_any_cast'
  what():  bad any_cast

Explain in short why the runtime error occurred in the main function.

(An answer up to 40 words is sufficient)

You are working on a calculator application where users can input a mathematical expression such as: (3 + 5) * (2 - 4).

To correctly evaluate this expression, the application needs to validate the expression and ensure that the parentheses are balanced. The balanced parentheses are crucial for determining the order of operations and evaluating the expression correctly.

You have used an AI assistant to generate the following function to check if the parentheses in an expression are balanced:

bool isBalanced(const std::string& parentheses)
{
    std::stack<char> stack;
    std::unordered_set<char> opening = { '(', '[', '{' };
    std::unordered_set<char> closing = { ')', ']', '}' };
    std::unordered_map<char, char> pairs =
    {
        { ')', '(' },
        { ']', '[' },
        { '}', '{' }
    };

    for (char c : parentheses)
    {
        if (opening.contains(c))
        {
            stack.push(c);
        }
        else if (closing.contains(c))
        {
            if (stack.empty() || stack.top() != pairs[c])
            {
                return false;
            }
            stack.pop();
        }
    }

    return stack.empty();
}

What is correct for the given function?