Today I have got an onsite interview. I have met four interviewers. From each of them I have got half part about work exprience related with the amazon leadership principles and half about technical question.\n\nThe technical part consisted of two design questions and two algorithms.\n\n1. First design question is to think about a bookstore system. The database diagram, and some details.\n\n2. design a search filter, whiteboard coding, and I had to refactor and apply some design patterns when the interviwer add some more details.\n\n3. First I got [#155 Min Stack](https://leetcode.com/problems/min-stack/), but the interviewer discovered that I had known the question so he changed to another one similar to [#387](https://leetcode.com/problems/first-unique-character-in-a-string/) in streaming. Design a data structure that supports two operations, one is add number, second is getFirstNoDuplicatedNumber.\n\n4. serialize and deserialize a binary tree [#297](https://leetcode.com/problems/serialize-and-deserialize-binary-tree/) and [my solution to this](https://leetcode.com/problems/serialize-and-deserialize-binary-tree/discuss/502021/Share-my-level-order-traversal-Java-solution).\n\n\nI hope I\'m lucky enough

Today I have got an onsite interview. I have met four interviewers. From each of them I have got half part about work exprience related with the amazon leadersh