The technical interview consisted of a conference call with two Spotify Data Engineers. It began with a few general data structure questions, such as when to use a linked list and the different ways to search for an element in a binary tree, followed by some statistical questions and common big data issues.

Then we moved to the coding part. I was asked to code a function to build Pascal's triangle. I did it functionally, then iteratively, and I was asked how to improve the complexity of my algorithm. I did struggle a bit on that part.

We ended with some SQL queries to write; nothing difficult.

How can we modify a linked list to be able to go backward?