Amazon

One technical question was asked, followed by questions on how to make the algorithm efficient. Explain the approach and talk about your thinking process. Ask questions to get your doubts cleared.

I couldn't even open the assessment, and the support team wasn't helpful at all. They kept asking me the same questions and would continue to tell me that the assessment link was about to expire whenever I told them it didn't work.

They interview you on the fundamentals of optimizing code to be more efficient or simpler, with concepts of data structures, recursion, and so on. They may ask you to write code to check if a word is a palindrome.