Whatsapp Software Engineer interview experience

Within a week, I was invited to an on-campus interview, and that first part actually felt pretty manageable. They had me implement a linked list with a few special operations like prepend and reverse, including some runtime requirements. After that, they asked about parallelism, which was a bit of a jump but still not overwhelming.

A week or so later, I was brought in for an onsite that turned the difficulty way up. It was a run of three technical/design interviews back-to-back, each lasting about an hour. The first two were data-structure questions that felt extremely hard, and the design