CDK Global Senior Java Engineer interview questions

No matter how nice and knowledgeable recruiter sounds if he tells you they are paying below market rate do not go further. Anyway, I agreed to phone screen. The interviewer was over 30 minutes late. I am not a native speaker myself but when on the other side there is a person who speaks worse than me it would not end very well. After half an hour of a pep talk, I got one of this puzzles from interview books to solve. I haven't seen this one before so definitely, my solution was not great.