🚀 Interview Experience | Python Backend Role | 2 Rounds + LRU Cache | Rejected Despite Correct Solution 😅

📅 Round 1 (26 June)

The first round was mostly discussion-based.

Topics Covered

• 🏗️ System Design of my current projects
• 🐍 Python fundamentals
• 🤖 AI projects and practical usage

The interviewer spent a good amount of time discussing my architecture decisions and how I had built AI-powered solutions at work.

📅 Round 2 (30 June)

This round focused on:

• 📌 Deep dive into my projects
• 🤖 How I use AI in my day-to-day development workflow
• 💻 1 Coding Question

💻 DSA Question — Implement SmartCache (LRU Cache)

Design a cache with limited capacity.

Implement:

• SmartCache(int capacity)
• get(int key)
• put(int key, int value)

Requirements

• Return -1 if key doesn't exist.
• Every access makes the key Most Recently Used.
• If cache is full, evict the Least Recently Used (LRU) item.

💡 Expected Approach

Use:

✅ HashMap → O(1) lookup

✅ Doubly Linked List → Maintain usage order

Operations:

• get() → Move node to front

• put()

  • Update existing → Move to front
  • If full → Remove tail (LRU)

⏱️ Complexity

• get() → O(1)
• put() → O(1)
• Space → O(capacity)

🧪 Follow-up

After writing the solution, the interviewer asked me to:

• Run through multiple test cases
• Explain every pointer update
• Justify why both operations remain O(1)
• Discuss edge cases (capacity = 1, updating existing keys, repeated gets)

Everything went smoothly, and the follow-up discussion was positive.

✅ Verdict

❌ Rejected

The feedback was that the role was primarily for a Python Developer.

Although:

• ✅ My approach was correct
• ✅ My Java implementation was correct
• ✅ I cleared the dry run
• ✅ I answered all follow-up questions

...the expectation was to code in Python, while I chose Java.

📚 Takeaway

For language-specific backend roles, always ask the interviewer which programming language they prefer before starting the coding round. A correct solution isn't always enough if the interview is evaluating proficiency in a particular language.

Hopefully this experience helps someone preparing for similar interviews. Good luck! 🚀