Amazon Operating Systems interview questions

I applied to Amazon Dresden for internship. After a week, they sent me a mail for a phone interview. I wasn't very successful but tried to answer all the questions and done the coding part fair enough. But the engineer said that we also need to do a Codility challenge to be sure you can code because I wasn't much efficient at coding. After a few days, I solved the Codility challenge which I had 2 hours to solve 4 problems in C. The problems weren't very difficult. I couldn't solve all questions,d done the first three fully and coded last one but it wasn't compiling. After that, I passed the coding challenge and made a phone interview again the manager and he asked me behavioral questions. After that, they declined me.