The first part was the Amazon Leadership Principles question.

Then, there was a LeetCode Medium question. Initially, I solved it in a suboptimal way, and we discussed the time and space complexity. The interviewer was helpful and kept giving hints to solve the issue optimally.

The LP question was something like: Tell about a situation when you had to deal with a very time-constrained project or task.

Design a data structure that tracks visitors in a queue with the following requirements:

• Possibility to return the last person in the queue who visited only once.
• All operations must have O(1) time complexity.

Here's an example:

visit("Alice") -> Queue: [Alice] visit("Bob") -> Queue: [Alice, Bob] visit("Charlie") -> Queue: [Alice, Bob, Charlie] visit("Bob") -> Queue: [Alice, Charlie] (Bob removed because second visit) get_last_unique() -> Returns "Charlie" visit("David") -> Queue: [Alice, Charlie, David] visit("Charlie") -> Queue: [Alice, David] (Charlie removed because second visit) get_last_unique() -> Returns "David"