Singapore Economic Development Board Senior .NET Full Stack Developer interview questions

First round: They will send me a HackerRank coding test, 50 minutes to complete. The test does not allow to use any Linq or build in method. So it requires to do it in a very manual way which I feel very not familiar as my daily job doesn't do it in this way. Second round: Online live programming with the technical team. Asked me some questions to test the knowledge level. Then it given me 2 coding tests. First question is to find the recursive output. No coding is allowed. Second question is to get a list without any duplicated elements. No linq or built-in function. Again, they said they want to test my logic thinking.