I am not particularly good at competitive programming, but at some point I did invest quite some time into it. Contrary to my username I have a pretty decent memory and I can remember easily if I've solved something similar.

At some point I've interviewed for a company who gave me four exercises to solve in an hour. Normally, it would've been impossible to solve them without previous knowledge. Funny part is that I knew the idea for all 4 and the only difficulty was to write things quick enough so I can finish everything in time. 57 minutes later, I was finishing all of them, to the surprise of the interviewers who were watching me coding.

I had the all time best score for that company, and everyone thought of me I am some kind of genius, which was certainly not true, because I know my limits, and I am far from it.

Nevertheless, everyone was a little disappointed by me in the next 6 months. I was quite junior, and had junior problems.