The first round was through University Recruiting. The on-campus interview had one tech question: check if you have a valid combination of '(', '{', '['.

The second round, the final round, was on-site in Seattle. Each interview had a 45-minute duration with a 15-minute break in between, for a total of 4 interviews.

• First interview: Given a pointer to a head node that contains two pointers pointing to any other two nodes (like a simplified graph), you need to make a deep copy of this graph.
• Second interview: Check if a BST is a valid BST.
• Third interview: Given a list of stock prices, you need to find the dates to buy and sell the stock to maximize profit.
• Fourth interview: You have a stream, and you need to check if the stream contains a specific string. The stream can indicate if it has reached EOF. You cannot use any STL; you need to write strlen if you require it, and you need to write IsSubstring if you want to use it.

The first and the last ones are fairly complicated.

Mainly because for the first one, you need to DFS/BFS the graph and then use a hashmap to prevent re-creating existing nodes.

The second is a test for your pointer arithmetic and manipulation.