I had been given the HackerRank as a prescreen, then I interviewed onsite at the Seattle office.

HackerRank questions:

• Stickers
• Delete and Earn

Onsite Questions:

I had 4 rounds:

1. System Design -- Design Slack Messenger.
2. Manager -- Culture fit round.
3. Coding -- Find common words from an array of books.
   • Get API will give words in a book.
   • Follow-up: Find the top N common words. (I did the sorting here, but I guess they were expecting a Priority Queue or something. I come from a JavaScript background, so fancy data structures are new to me).
   • Time complexity for the same.
4. Coding -- Find the first affected node given a set of nodes.
   • Get API will return if a node is healthy or not and also will return a set of child nodes which all will have the same health status of the parent.
   • Time Complexity for the same.
   • I found it similar to a journey problem to find the starting node. I used +1 for the main node as the source and -1 for all the child nodes as they represent the destination. I added them to a dictionary, and the result is the nodes with a value >= 0. The interviewer said they had not seen this approach before. We ran a couple of test cases; everything was working as expected.
   • Follow-up with more test cases and failure points in the algorithm (API can error out).

I thought I did extremely well in all the rounds, but they sent me a rejection :(

FML.

Hacker Rank questions:

1. Stickers
2. Delete and earn

Onsite:

• System Design: Design Slack Messenger.
• Coding: Find common words from an array of books.
• Coding: Find the first affected node given a set of nodes.