Leetcode.com is a website where you practice FAANG-style interview questions
They don't want to write code during the interview. Some complain about needing to practice, which I can't understand. Me, I'm pushing 50 and I'd be wary of joining a team who got hired without writing code.
I despise Leetcode style problems because I think being asked to give an impromptu CS lecture is not a great interview technique. I wrote code in the interview for my current job, but it wasn’t “find the longest palindromic substring of a given string in linear time.”
So leetcode is code that is written by the interviewee during an interview? Sounds tough. I never had to do that. I would probably clam up and fail.
That is related, but leetcode is actually a website dedicated to these kinds of interview problems: