Technical Interview: Coding & System Thinking

This page covers practical strategies for coding interviews: problem breakdown, writing correct and efficient code, communicating clearly, and presenting trade-offs.

Why this matters for interviews

Technical interviews evaluate your ability to solve problems under time pressure, reason about complexity, and communicate solutions — core skills for engineering roles.

Problem-solving steps (repeatable)

1. Clarify requirements & edge cases.
2. State constraints and expected input sizes.
3. Propose a high-level approach and complexity.
4. Write working code; handle edge cases.
5. Optimize and explain trade-offs.

Coding tips

• Write simple, correct solution first; then optimize.
• Use descriptive variable names and short helper functions.
• Talk through examples while coding.
• Test with 2–3 edge cases before finishing.

Complexity and trade-offs

• Always state time and space complexity.
• If proposing a hashed or sorted approach, mention worst-case scenarios.

System-design primer (for mid/senior rounds)

• Start with requirements, sketch high-level components, data flows, and bottlenecks.
• Discuss scaling, caching, consistency, and trade-offs briefly.

Sample practice problems

• Array sliding window (sum / max subarray)
• BFS/DFS on graphs
• Hashmaps for frequency counting
• Simple design: URL shortener overview

Quick checklist for interviews

• Clarified input/output? Edge cases listed? Code handles them? Complexity explained?