Requirements and game rules in LLD - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Functional Requirements

Which of the following best describes a functional requirement in system design?

A A description of the user interface colors and fonts.

B A description of the system's hardware and software environment.

C A list of constraints like budget and deadlines.

D A description of what the system should do, such as features and behaviors.

💡 Hint

Think about what the system must perform or provide.

Functional requirements specify what the system should do, including features and behaviors. Other options describe non-functional requirements or design details.

❓ Architecture

intermediate

Choosing the Right Architecture Style

You need to design a system that supports many users simultaneously and can be updated without downtime. Which architecture style fits best?

A Layered architecture with tightly coupled layers.

B Monolithic architecture with a single deployable unit.

C Microservices architecture with independent deployable services.

D Client-server architecture with a single server handling all requests.

💡 Hint

Consider scalability and independent updates.

Microservices allow independent deployment and scaling of services, supporting many users and updates without downtime.

❓ scaling

advanced

Scaling a Real-Time Chat Application

Your chat app must handle millions of users sending messages simultaneously. Which approach best supports this scale?

A Implement horizontal scaling with multiple stateless servers and message queues.

B Store messages only on client devices to reduce server load.

C Use a single database server to store all messages.

D Use a monolithic server with vertical scaling (more CPU and RAM).

💡 Hint

Think about distributing load and handling many simultaneous connections.

Horizontal scaling with stateless servers and message queues distributes load and supports many users efficiently.

❓ tradeoff

advanced

Tradeoffs in Consistency Models

In a distributed system, choosing eventual consistency over strong consistency means:

A Data is always immediately consistent across all nodes.

B Data may be temporarily inconsistent but improves availability and performance.

C The system cannot handle network partitions.

D Users will never see stale data.

💡 Hint

Consider availability and performance tradeoffs.

Eventual consistency allows temporary inconsistencies to improve availability and performance, unlike strong consistency which requires immediate synchronization.

❓ estimation

expert

Estimating Storage for a Video Streaming Service

You design a video streaming service storing 1 million videos averaging 500MB each. How much storage is needed to store all videos with 3 copies for redundancy?

A Approximately 1.5 petabytes (PB)

B Approximately 500 terabytes (TB)

C Approximately 150 terabytes (TB)

D Approximately 3 petabytes (PB)

💡 Hint

Calculate total size then multiply by number of copies.

1 million videos × 500MB = 500 million MB = 500 TB. With 3 copies, total is 500 TB × 3 = 1.5 PB.