I strongly recommend not to waste time and energy interviewing for this company. I don't understand how they can expect a person to solve three long and medium-level, fully working (meaning fully compiling) questions in 45 minutes during their Karat screening interview.

Let me give you more insight: if you provide the proper approach for the third question and write the code as well, but don't get time to compile it, they will not consider your third question at all. Also, the Karat interviewers follow a strict procedure:

1. Write the code.
2. After writing, compile it and fix any compilation errors.
3. Run it on some test cases.
4. State the Time Complexity and Space Complexity. (You are not allowed to mention the complexities before completing the second step, as they state they only consider it after that. Generally, any good company will ask you about complexities at the start, once you explain your approach.)

It's a one-sided interview where the interviewer doesn't care about an optimized solution. They also don't interact. So, focus on solving the maximum number of questions possible without interacting at all, as they don't care about anything else except your three fully working codes (as per the steps above).

LeetCode medium-level graph questions. And, most of the questions use hash maps as well.