Hi, I was asked two medium level questions.

Question 1: https://leetcode.com/problems/remove-nth-node-from-end-of-list/
Question 2: https://leetcode.com/problems/minimum-remove-to-make-valid-parentheses/

Gave O(n) time and O(1) space solution for first one.
Gave O(n) time and O(n) space solution [using StringBuilder] for second one.

Yoe: 3.5 yrs