I was asked the following problems:

1. https://leetcode.com/problems/minimum-remove-to-make-valid-parentheses
2. Given a N-ary tree and you are standing at the root of the tree. There are some special nodes, you need to find the min length path such that you start from the root, visit all the spcial nodes and come back to the root.

I have not seen the second proble on LC.