YOE: 5 years
Current Company: mid level startup

Recruiter reached out to me on linkedIn

Round 1: DSA Round [1 hr]

1. https://leetcode.com/problems/find-the-winner-of-the-circular-game/description/ - solution in O(n) and O(1) space complexity was required
2. https://leetcode.com/problems/maximum-sum-of-distinct-subarrays-with-length-k/description/

The interviewer asked me to code the solution on IDE of my choice.

Round 1: HLD + LLD [1 hr]

1. I was tasked with designing and implementing a firewall system.
2. Initially, I gathered the requirements: Source and destination IP ranges were specified.
3. The primary task was to write a function to allow or disallow requests based on the source and destination IPs.
4. I initially proposed storing the IP ranges in a hashmap, but this approach proved too costly in terms of time and space complexity.
5. After reevaluating the problem from a pattern-matching perspective, I developed a solution that utilized a Trie.
6. The interviewer asked me to implement the solution using a Trie.Initially, I maintained separate tries for source IPs and destination IPs, but this approach was also inefficient.
7. Eventually, I combined the source and destination IP ranges into the same trie to streamline the process.
8. I coded the solution and demonstrated its functionality through various examples.

Round 4: Director Round [in-person]

1. I was asked to explain the architecture of one of my projects.
2. Then he asked me to design Coursera like system
3. The main problem we solved in building the system was enterprising licensing of few courses
4. Needed to handle race conditions + locking
5. Explained the architecture + database choices + CAP theorem in different scenarios
6. Database Schema in detail
7. APIs in detail
8. Few behavorial questions in the end

Within two weeks got the offer letter