Q1. Given Arbitarty List of Nodes possibly duplicates find the Root node. (Solved with Map and parent Pointers, found the Key-value pair which is None)

Q2. Build a AbstractDataStructure Build it which supports 1. put 2. get 3. remove 4. last_used (Mentioned the Linked List approach, but had 5 mins remianing so coded up Stack based approach to track last used elemnent)

Result - Passed Moving to Onsite.

Thanks