Round1: coding a) https://leetcode.com/problems/top-k-frequent-words/ b) lowest common ancestor for n-ary tree with parent pointers

Round2: coding. a) https://leetcode.com/problems/validate-binary-search-tree/ b) Longest string without repeating characters https://leetcode.com/problems/longest-substring-without-repeating-characters/ (Had more time, so extension asked: longest substring any character can repeat at most 2 times)

I was able to solve all, waiting for feedback.