Piece movement rules (polymorphism) in LLD - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding polymorphism in piece movement

In a chess game design, each piece moves differently. How does polymorphism help in implementing movement rules?

A It uses static methods to define movement rules that cannot be overridden.

B It forces all pieces to share the same movement logic, reducing code duplication.

C It stores all movement rules in a single global function that all pieces call.

D It allows each piece class to define its own move method, enabling different movement behaviors through a common interface.

💡 Hint

Think about how different pieces can have unique move logic but still be treated as the same type.

Polymorphism allows each piece subclass to implement its own move method. This means the game can call move on any piece without knowing its exact type, and the correct movement rules will apply.

❓ Architecture

intermediate

Designing piece movement with polymorphism

You are designing a chess game. Which class design best uses polymorphism for piece movement?

A Use a global function that takes piece type and position to calculate moves, without classes.

B Create a Piece class with a single move() method that uses if-else to check piece type and apply movement.

C Create a base Piece class with an abstract move() method. Each piece subclass implements move() with its own logic.

D Define movement rules in a configuration file and parse them at runtime without polymorphism.

💡 Hint

Consider how polymorphism avoids complex conditionals and supports extensibility.

Using an abstract move() method in a base class and overriding it in subclasses is a classic polymorphic design. It keeps code clean and easy to extend.

❓ scaling

advanced

Scaling piece movement rules for new game variants

You want to add new chess variants with additional pieces and movement rules. How does polymorphism help scale your design?

A By allowing new piece classes to inherit from the base Piece class and override move(), new rules integrate seamlessly.

B By modifying the base Piece class move() method to include all new movement rules for every variant.

C By storing all movement rules in a single monolithic function that checks piece type and variant.

D By duplicating the entire codebase for each variant to handle different movement rules.

💡 Hint

Think about how inheritance and overriding support adding new behaviors without changing existing code.

Polymorphism allows new piece types to be added as subclasses with their own move implementations. This avoids changing existing code and supports easy extension.

❓ tradeoff

advanced

Tradeoffs of polymorphism vs conditional logic in piece movement

What is a key tradeoff when using polymorphism for piece movement rules compared to using conditional statements inside a single method?

A Polymorphism reduces the number of classes but makes adding new pieces harder.

B Polymorphism improves code clarity and extensibility but may increase the number of classes and complexity.

C Using conditionals is more extensible and easier to maintain than polymorphism.

D Polymorphism always results in slower performance than conditionals.

💡 Hint

Consider maintainability and class count when choosing design approaches.

Polymorphism leads to cleaner, modular code and easier extension but can increase the number of classes and complexity of the class hierarchy.

❓ component

expert

Request flow for validating piece movement using polymorphism

In a chess game system, describe the flow of a move request using polymorphism to validate if a piece can move to a target square.

A Client sends move request → Game controller calls piece.move(target) → Piece subclass validates move → Returns valid/invalid → Controller updates board.

B Client sends move request → Game controller checks piece type → Calls global validateMove(piece, target) function → Updates board.

C Client sends move request → Game controller uses a switch-case on piece type to call specific validation functions → Updates board.

D Client sends move request → Board directly updates piece position without validation → Game controller logs move.

💡 Hint

Focus on how polymorphism lets the controller treat all pieces uniformly.

The controller calls move() on the piece object. Polymorphism ensures the correct subclass method runs to validate the move. This keeps the controller simple and extensible.