Board and piece hierarchy in LLD - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding inheritance in board and piece hierarchy

In a board game design, which class should be the base class to represent all pieces on the board?

A A <strong>Game</strong> class that manages the rules and flow.

B A <strong>Player</strong> class that owns pieces.

C A <strong>Board</strong> class that contains all pieces and their positions.

D A generic <strong>Piece</strong> class that all specific pieces inherit from.

💡 Hint

Think about what all pieces share regardless of type.

The Piece class is the base because it represents common properties and behaviors for all pieces, such as position and movement rules.

❓ Architecture

intermediate

Designing the board class for scalability

Which design choice best supports a scalable board that can handle different game types and sizes?

A Use a fixed-size 2D array inside the <strong>Board</strong> class for all games.

B Implement the <strong>Board</strong> class with a dynamic data structure like a map or dictionary keyed by coordinates.

C Store pieces directly inside the <strong>Piece</strong> class without a board container.

D Use global variables to track piece positions outside any class.

💡 Hint

Consider flexibility for different board sizes and shapes.

A dynamic data structure keyed by coordinates allows the board to adapt to various sizes and shapes, supporting multiple game types.

❓ scaling

advanced

Handling piece movement validation efficiently

For a complex game with many piece types and movement rules, which approach best scales validation logic?

A Define movement rules inside each <strong>Piece</strong> subclass using polymorphism.

B Hardcode movement rules in the UI layer.

C Use a global function that checks moves for all pieces without class methods.

D Put all movement rules in a single large method inside the <strong>Board</strong> class.

💡 Hint

Think about how to keep code organized and easy to extend.

Using polymorphism lets each piece class handle its own movement rules, making the system modular and easier to maintain as new pieces are added.

❓ tradeoff

advanced

Choosing between composition and inheritance for piece abilities

Which design choice balances flexibility and code reuse when pieces have multiple abilities?

A Use composition by creating separate ability classes and attaching them to pieces.

B Use deep inheritance chains where each subclass adds one ability.

C Duplicate ability code in each piece subclass that needs it.

D Implement all abilities in the base <strong>Piece</strong> class with flags.

💡 Hint

Consider how to add or remove abilities without rewriting classes.

Composition allows abilities to be modular and reusable, avoiding rigid inheritance hierarchies and code duplication.

❓ estimation

expert

Estimating memory usage for a large chess-like game

Estimate the approximate memory needed to store the state of a 100x100 board with 10,000 pieces, each piece storing position (2 integers), type (1 byte), and owner (1 byte). Assume 4 bytes per integer and ignore overhead.

A About 600 KB

B About 6 MB

C About 100 KB

D About 600 MB

💡 Hint

Calculate bytes per piece and multiply by number of pieces.

Each piece: 2 integers (4+4=8 bytes) + type (1 byte) + owner (1 byte) = 10 bytes. 10,000 pieces × 10 bytes = 100,000 bytes ≈ 100 KB (C).