When to use which structural pattern in LLD - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Choosing the right structural pattern for flexible UI components

You are designing a UI library where components can be combined in different ways. Which structural pattern is best when you want to treat individual components and groups of components uniformly?

A Facade pattern

B Composite pattern

C Adapter pattern

D Decorator pattern

💡 Hint

Think about a pattern that lets you work with single objects and collections the same way.

The Composite pattern allows you to treat individual objects and compositions of objects uniformly, which is ideal for flexible UI components.

❓ Architecture

intermediate

Using Facade pattern for simplifying complex subsystems

You have a complex system with many classes and interfaces. You want to provide a simple interface to clients without exposing the complexity. Which structural pattern fits best?

A Facade pattern

B Proxy pattern

C Bridge pattern

D Flyweight pattern

💡 Hint

Look for a pattern that provides a simplified interface to a complex system.

The Facade pattern provides a unified and simple interface to a complex subsystem, hiding its complexity from clients.

❓ scaling

advanced

Scaling object creation with Flyweight pattern

You need to create millions of similar objects in a memory-efficient way. Which structural pattern helps reduce memory usage by sharing common parts?

A Adapter pattern

B Decorator pattern

C Flyweight pattern

D Bridge pattern

💡 Hint

Think about sharing intrinsic state to save memory.

The Flyweight pattern shares common parts of objects to reduce memory usage when many similar objects are needed.

❓ tradeoff

advanced

Tradeoffs between Adapter and Bridge patterns

You want to decouple an abstraction from its implementation so they can vary independently. Which pattern is more suitable, and what is a key difference from the other?

A Bridge; it separates abstraction and implementation, while Adapter converts one interface to another

B Bridge; it converts one interface to another, while Adapter separates abstraction and implementation

C Adapter; it shares objects to save memory, while Bridge provides a simple interface

D Bridge; it shares objects to save memory, while Adapter provides a simple interface

💡 Hint

Focus on the purpose of each pattern regarding interfaces and abstraction.

Bridge separates abstraction from implementation to allow them to vary independently. Adapter changes one interface to another to make incompatible interfaces work together.

❓ component

expert

Designing a plugin system with Decorator pattern

You are building a plugin system where features can be added dynamically to objects without changing their code. Which structural pattern allows wrapping objects to add responsibilities at runtime?

A Flyweight pattern

B Facade pattern

C Composite pattern

D Decorator pattern

💡 Hint

Consider a pattern that wraps objects to add new behavior dynamically.

The Decorator pattern wraps objects to add responsibilities dynamically without modifying the original object code, ideal for plugin systems.