Booking.com IOS Developer interview questions

First I was contacted by a recruiter on LinkedIn and I agreed to have a short chat with her about my experience. The second phase was a hackerrank test with 4 questions (I posted them below). They can also be found online. The time limit was 75 minutes I think. For the third phase I had another chat with the HR person. Not really sure why, it was only to confirm that I want to move to Amsterdam. The fourth phase was a technical phone interview. In my opinion this part was the worst. It was also the one I failed. They ask you a algo/data structures question and a iOS question (I posted both below). I think that they don't allocate enough time for these questions, since in my case the algo question was a hard leetcode question. For the iOS question they just have you write code but without giving any sort of explanation. I know you have to ask clarifying questions but in this case every time I asked something it was answered with another question. The fact that the interviewers had the charisma of a match stick didn't help either. All in all it was a negative experience. I was even more let down at the end when they told me they don't write unit tests for the code that they write...

Worst interview ever. I applied on their website. First, the HR contacted you and sent you the wrong HackerRank challenge. Then they sent you the correct challenge. After the challenge, HR late for the scheduled call and told you no vacancies available for the current team. Referred me to another team but then rejected me after the second call.