I have been to two rounds: a preliminary/motivation interview via video call. Having passed that, I was given homework/a test.

This second one was a HackerRank test with around 20-25 quiz questions and 4 or 5 coding tasks. The quiz was mainly in-depth questions about SOLID principles, design patterns, and such, then some algorithms for coding.

I had 5 days to submit the online task but only 90 minutes (no breaks) to finish once started.

I strongly suggest practicing on HackerRank before starting, so that you get used to the input/output system you'll have to work with. Opening an IDE can also be very helpful for avoiding syntactical errors.

I learned the importance of these advices by my own mistake – I got stuck and ran out of time. Thus, I didn't make it to the next round. But, as far as I know, there would have been one or two technical interviews in person, and then one with HR.

Also, since TW is a financial institution, they do a background screening, which takes about two weeks.

Validate whether the input can be a binary search tree traversal.