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OA: There are five questions in total. The SQL question will use `GROUP BY` and CTEs. The coding questions are medium-level array and string questions. The sliding window technique will be tested. (You won't pass all tests if your solution is O(n^2

For the online assessment, there were 5 multiple-choice questions and 2 coding questions. The coding questions were around medium LeetCode level. Then, you were invited to do the interview.

1. Introduce for both sides. 2. Coding: Merge two binary search trees to build one BST. (Inorder traversal + sorted array merge + build a new tree from inorder array) 3. Ask reverse questions. Total time: 45 minutes.