Tinkoff Digital Intern Software Developer interview questions

I filled out a questionnaire on their website. There were about 30 questions, including both questions about skills and experience and a request to tell something about yourself. Since I was applying as a student, I also had to attach two letters of recommendation from professors/research supervisors. After that, there was a contest on their platform on algorithms. It was 5 hours for 8 problems, I would say three were easy, 4 were on advanced level graphs and the last one was more on number theory. I only managed to completely solve 4 problems. Based on the results of the contest, I was invited to one technical interview. At first there was a simple problem on strings, I quickly said out loud how to write it and immediately went on to the next one. There I first thought that the problem was a dynamic programming problem, but then I realized that I had to build an island tree and then choose a maximum weight pair combination from it.