Oracle Applications Developer interview questions

1st Round:They asked about Coding questions and told to Optimize the solution 2nd Round:They asked about my resume and about the projects i have done 3rd Round:About the more complex side of my projects and questions on that combined With HR questions

This was a campus placement. The company came for 2 roles Application developer and Server Technology. The first round was MCQ online test. This was pretty easy except the flow diagrams which were a bit tricky to solved. The next round was the interview round. It was done over a zoom call. In the 1st round of interview, I was asked about myself. I also told the interviewer about my projects. Then he asked about some basic data structures and I told all the answers. They were pretty easy to be honest. Next he told me to write a program to find Kth largest element in a linked list. I had to think about this. The first thing which came to my mind was what extra work was I doing while sorting to find "Kth largest" element. I knew I had to do partition scheme of quick sort to search the element but when I was telling him the approach, he stopped me and told just to write the code. So I have 8 mins to write the code and at the same time I have to write the linked list class implementation(5min) and then when I was writing the function for it( a driver and a partition scheme function ) he stopped me and told the time is up. He later asked me about the explanation and I told him the approach and it was working perfectly fine and told we cannot do better than O(n). After the interview I was content with my explanation and later checked that it was the optimal solution. However I wasn't called for next round interview despite giving all the right answers. I was pretty depressed as to why I got rejected. I ruminated long for where I went wrong and still not able to find out :(