Architect DSA Interview

Congratulations. You have mastered the internals of computer science. In this final module, we summarize the 3 types of questions you will face at FAANG level interviews.

1. The "Scale Up" Question

Question: "You have a list of 1 billion IDs. How do you find the unique IDs in under 500MB of RAM?"

Architect Answer: "I wouldn't use a HashSet (too much RAM). I would use a Bloom Filter (probabilistic) or a Bitset (bit-map) if the IDs are numeric. This allows me to trade a tiny bit of accuracy for a 99% reduction in memory footprint."

2. The Algorithmic Trade-off

Question: "Why would you choose a slower algorithm on purpose?"

Architect Answer: "Reliability and Maintainability. For example, replacing a complex Recursive DP with a simple iterative loop might lose 5% speed but prevents **Stack Overflow crashes** and makes the code 10x easier for the dev team to debug at 3 AM. A senior architect optimizes for the **System**, not just the algorithm."

DSA MASTERY COMPLETE.

You are now equipped with the tools to solve any engineering problem. Use them wisely. Build something great.