Round 1: 
1. A BT is provided, flood it with right and left siblings. 
2. Given n, write a function to generate all combinations of n paired well-formed parentheses.  
3. Explain how TreeMap works internally (basically red-black tree). 

Round 2:
1. Discussion on the internship work. 
2. Celebrity Problem. 
3. Discussion about how to optimize the current performance of your favorite app.
4. LRU cache. 
5. Basic HR questions