Meta Software Developer Internship interview questions

Video conference where I was asked to do an LC easy and an LC medium. Solved both questions efficiently and interviewer seemed satisfy with the solutions. However for the second question it said you would get bonus points if you knew how to achieve an O(n) complexity which was by implementing quick sort. At the time I had no idea what was quick sort so my solution was O(nlogn), which is still good. I got rejected however even though I thought I did pretty good.