What technical interview questions should a software engineer prepare?

Software engineers should prepare for a variety of technical interview questions that test their coding, system design, problem-solving, and behavioral skills. Here’s a comprehensive list of the most important technical interview topics and sample questions to practice:

1. Coding and Algorithm Questions

These questions test your ability to write efficient code and solve problems.

Common Questions

• Reverse a string without using a built-in function.
• Find the two numbers in an array that add up to a target sum (Two Sum Problem).
• Implement merge sort or quick sort.
• Find the longest substring without repeating characters.
• Determine if a linked list has a cycle.

Key Topics

• Arrays, strings, and linked lists
• Sorting and searching algorithms
• Recursion and dynamic programming

Resources

• Grokking the Coding Interview: Patterns for Coding Questions
• Grokking Data Structures & Algorithms

2. System Design Questions

For mid-to-senior-level roles, these questions evaluate your ability to design scalable and efficient systems.

Common Questions

• Design a URL shortening service like Bit.ly.
• Design an e-commerce system with product catalog, search, and payment features.
• Create a high-level design for a messaging system like WhatsApp.
• How would you design a distributed caching system?

Key Topics

• Database design (SQL vs. NoSQL)
• Scalability, load balancing, and caching
• API design and microservices architecture

Resources

• Grokking the System Design Interview
• Grokking the Advanced System Design Interview

3. Data Structures

Strong knowledge of data structures is essential for solving coding problems efficiently.

Common Questions

• Implement a stack using an array or linked list.
• Traverse a binary tree (in-order, pre-order, and post-order).
• Find the shortest path in a graph using Dijkstra’s algorithm.
• Implement a hash map.

Key Topics

• Stacks, queues, and heaps
• Trees and graphs
• Hash tables and dictionaries
• Priority queues and tries

4. Programming Language-Specific Questions

Be ready to answer questions specific to the language required for the role.

Common Questions

• Explain the difference between let, var, and const in JavaScript.
• How does Python handle memory management and garbage collection?
• What are the key differences between Java and C++?
• Write a SQL query to find duplicate records in a table.

Key Topics

• Language syntax and semantics
• Debugging and error handling
• Language-specific libraries and tools

5. Behavioral Technical Questions

These questions evaluate your problem-solving approach, teamwork, and communication skills.

Common Questions

• Describe a technical problem you solved and how you approached it.
• How do you handle disagreements about technical decisions within a team?
• Share an example of when you optimized an inefficient process or application.

Resource

• Grokking Modern Behavioral Interview

6. Database and Query Optimization

Knowledge of databases is crucial for backend and full-stack roles.

Common Questions

• Write a query to find the second-highest salary in a table.
• Explain the difference between a clustered and non-clustered index.
• What are normalization and denormalization? When would you use each?
• How would you optimize a slow SQL query?

Key Topics

• SQL and relational databases
• NoSQL concepts
• Indexing and performance tuning

7. DevOps and Deployment

These questions may appear for roles involving CI/CD, deployment, or system operations.

Common Questions

• Explain how a CI/CD pipeline works.
• What’s the difference between Docker and Kubernetes?
• How would you monitor application performance in production?

8. Specialized Topics

For niche roles, prepare for questions in areas like machine learning, security, or frontend development.

Machine Learning

• What’s the difference between supervised and unsupervised learning?
• How would you evaluate the accuracy of a machine learning model?

Security

• What are the most common types of cyberattacks? How do you mitigate them?
• How does HTTPS ensure secure communication?

Frontend Development

• Explain the browser rendering process for a webpage.
• What’s the difference between React and Angular?

Additional Preparation Tips

• Mock Interviews: Use Coding Mock Interview or System Design Mock Interview for real-world practice.
• Company-Specific Practice: Research company-specific patterns with blogs like Mastering the FAANG Interview.
• Keep Learning: Pair interview prep with skill-building courses for advanced coding or design knowledge.

Conclusion

To prepare for a software engineering interview, focus on coding, data structures, system design, and behavioral questions. Leverage structured resources like Grokking the Coding Interview and mock interviews to refine your skills and boost confidence.