Amazon Non Software Development Engineer interview questions

Question : Find the Lowest Common Parent between the given nodes of an BST.

One of the recruiters will send an email to setup the interview, a date will be chosen of your choice. Some employee will call on that day and will introduce himself give description of his team. First interview went well. He will ask coding questions on algorithms, data structures, OOPS. Second interview is of same pattern. This time my interviewer did not give any hints whatsoever. He waited till I was not able to solve and ended the interview.