Bloomberg Senior Software Engineer interview questions

the interview is was pretty straight forward but they demand more accurate answers. I was contacted by a recruiter and opted for an interview 2 months later in order to prepare. I bombed the online assessment.

It was very straightforward session. a leetcode medium level question. I found the algorithm very quickly because it was not new problem for me. I implemented with some mistakes but found and fixed all of them myself, after few test cases. after that he asked few design questions like how to protect the valid inputs, stuff like that. I answered all. it was quite positive and i believed i am going to next step. what happened? in just two days rejected! why? I am very sad now.