They have a 3-round application process.

Round 1 is a phone call from someone from HR. Round 2 is a technical interview with 2 developers. Round 3 is a face-to-face interview at his office in Amsterdam.

In Round 1, the HR person will review your CV and ask about your previous experiences. You need to explain why you want to work for them.

Round 2 is the technical interview, but it's really great (if you like programming). They asked questions about algorithms and general array problems. Be prepared for complex algorithmic questions.

Given a list of non-negative integers, return the first unique number in this list (that appears only once).

Example: [1,1,2,3,56,4,7,4,3,2,56,1000]

// Expected result: 7