senior-coding-interview

Senior Coding Interview

Execute L6+ real-world coding interviews where the problem is building a small system, not solving an algorithm puzzle. The core differentiator at Staff+ level is not whether you can solve it, but how you solve it: clean abstractions, narrated reasoning, graceful iteration, and production sensibility.

When to Use

• Practicing real-world coding problems (in-memory stores, rate limiters, task schedulers)
• Reviewing interview code for senior-level signals
• Preparing communication strategy for live coding sessions
• Working through CodeSignal incremental-style problems
• Mock interview practice with follow-up extensions

NOT for:

• LeetCode/competitive programming (segment trees, suffix arrays, contest optimization)
• Behavioral interviews (use interview-loop-strategist)
• System design whiteboard with no code (use ml-system-design-interview)
• Resume or career strategy

---

The 4-Stage Approach

flowchart LR
    C[1. CLARIFY\n5 min] --> S[2. SKELETON\n20 min]
    S --> I[3. ITERATE\n10 min]
    I --> O[4. OPTIMIZE\n5 min]

    C -.- C1["Ask 3-5 questions\nRestate problem\nConfirm API contract\nIdentify edge cases"]
    S -.- S1["Data structures first\nPublic API methods\nCore logic\nManual test 1 case"]
    I -.- I1["Edge cases\nError handling\nFollow-up extensions\nRefactor if needed"]
    O -.- O1["Complexity analysis\nTrade-off discussion\nConcurrency mention\nScaling path"]

Stage 1: Clarify (5 minutes)

Goal: Demonstrate you think before coding. Ask questions that reveal ambiguity the interviewer planted intentionally.

Mandatory questions for every problem:

1. Scale: "How many items/requests are we expecting?" (determines data structure choice)
2. API surface: "Should this be a class with methods, or standalone functions?"
3. Constraints: "Are keys always strings? Can values be None/null?"
4. Concurrency: "Single-threaded for now, or should I consider thread safety?"
5. Error handling: "Should invalid input raise exceptions or return error values?"