I'm a recent graduate and got an invitation from Amazon Luxembourg for on-site interview.
1. I'm fairly good in coding (not in DP ofc).
2. Never used Leet Code, was active on Codeforces and Hackerrank.
3. Not good with OOPS (Object Oriented Programming) and System Design.
Any suggestions are welcome.
Start working from the bottom and to the top, and you should be good.