Why creational patterns manage object creation in LLD - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create an object using a creational pattern.

LLD

object = [1]()

Drag options to blanks, or click blank then click option'

AFactory

BBuilder

CSingleton

DObserver

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing Observer which is for event handling, not creation.

The Factory pattern is used to create objects without specifying the exact class.

2fill in blank

medium

Complete the code to ensure only one instance of a class is created.

LLD

class Singleton:
    _instance = None

    def __new__(cls):
        if [1] is None:
            cls._instance = super().__new__(cls)
        return cls._instance

Drag options to blanks, or click blank then click option'

Acls.instance

Bcls

Ccls._instance

Dcls._singleton

Attempts:

3 left

💡 Hint

Common Mistakes

Using cls.instance which is not defined.

The Singleton pattern checks if the instance exists using cls._instance.

3fill in blank

hard

Fix the error in the Builder pattern method to return the final product.

LLD

class Builder:
    def __init__(self):
        self.product = []

    def add_part(self, part):
        self.product.append(part)

    def get_result(self):
        return [1]

Drag options to blanks, or click blank then click option'

Aself

Bproduct

Cpart

Dself.product

Attempts:

3 left

💡 Hint

Common Mistakes

Returning 'product' without self causes a NameError.

The method should return the product stored in self.product.

4fill in blank

hard

Fill both blanks to create a Factory method that returns a new object.

LLD

def factory_method(type):
    if type == 'A':
        return [1]()
    else:
        return [2]()

Drag options to blanks, or click blank then click option'

AProductA

BProductB

CProductC

DProductD

Attempts:

3 left

💡 Hint

Common Mistakes

Using the same product class for both types.

The factory method returns ProductA or ProductB objects based on the type.

5fill in blank

hard

Fill all three blanks to complete the Singleton pattern implementation.

LLD

class Singleton:
    _instance = None

    def __new__(cls):
        if [1] is None:
            [2] = super().__new__(cls)
        return [3]

Drag options to blanks, or click blank then click option'

Acls._instance

Dcls

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names causing errors.

All blanks refer to the class variable cls._instance to ensure only one instance is created and returned.