Salesforce Member of Technical Staff Interview Experience — Three Rounds from Streaming Top K to Payment Design

Round 1

• Find the top K most frequent elements in an infinite data stream.
• Convert a sorted doubly linked list in place into a balanced binary search tree without creating any new nodes.

Round 2

I had to implement merge sort by hand:

1. Implement merge sort from scratch.
2. Explain its recursion tree in detail.

I also had to implement operations involving set bits and find all anagrams.

Round 3: System Design

Design a payment processing platform, with the discussion focused on:

1. Idempotency.
2. Retries.
3. Failure handling.