Twin Health Sr. Full Stack Software Engineer - Front End role interview questions

I was referred by a friend. 1) First round was 45 min Introductory round. Had a pleasant conversation with one of the Sr. Eng. managers. He asked me about my previous projects and some technical discussion. Received email for 2nd round after the conversation. 2) I scheduled the 2nd round - technical - backend(Java) in the next week. The interviewer jumped to the coding question directly without any other technical questions. I was asked a hard level leetcode question. For which I was able to come up with a solution in 5-10 mins and while explaining the steps I was able to complete the code. I explained the runtime and space complexity. I was expecting another coding question but the interviewer rather discussed more on the runtime and suggested to go another way for better runtime(which took most of the time). While I was halfway through the coding, the interviewer said time is almost up and we should wrap up the call. Received the standard rejection email the next morning. Was little disappointed as I was expecting a positive response.