I interviewed for Snapchat (onsite).

I had five tech interviews, and in all of them, I had to write and compile code. I was able to solve all questions and ran them with different test cases. Even the interviewers said positive things about my solutions. I also spoke about my thought process while coding and wrote clean, modularized code.

I'm really surprised and confused about what could have gone wrong. They didn't provide any feedback either :(

All they wrote was this:

"Thanks so much for your interest in Snap Inc. We really appreciate the time you invested in the application/interview process. Although we saw a lot of strengths in your background, we feel there isn’t the perfect match at this time, and we have decided not to proceed with your candidacy for Snap Inc.'s Software Engineer role."

Typical DS/Algo interview questions.