MongoDB Software Engineer interview experience

I ended up doing five rounds total, each with a different focus. The first was an algorithms coding task about intersections of two integer vectors. The second pushed into algorithms and data structures with something like deleting nodes from a binary tree and returning the resulting forest.

The third round was the hardest for me: concurrency. I was asked to implement a concurrent blocking queue, which tested my understanding of multithreading, condition variables, and synchronization. Then I had a system design round without code where I designed something around mapping integers to strings