I was applying through a referral. There were a promised 4-5 stages, with 3 technical interviews.

Unfortunately, after the 3rd tech interview, I was withdrawn from the process with the standard answer: "we have more technically skilled candidates." No other details were provided, and no feedback was given, even after I explicitly asked the recruiter.

Overall, the process was not bad, and I'm still glad I got the chance to join the team. All tasks were finished and worked. However, my solution for the last one was not optimal, and I didn't account for a corner case. I was able to handle it after receiving a clue.

Design a new data structure with O(1) time complexity for add/delete/get/get_random methods.

Why is accessing a value by key in a dictionary structure O(1) on average?

Write an algorithm to compress strings like AAAABB into A4B2 with no extra memory.