I have a small suggestion for LeetCode problem UI. We all know that in a real interview you have only 45 minutes to solve a problem. I suggest LeetCode to add timer in problem UI to track your time, so we will not spend more than 45 minutes on one problem. It will also be helpful to practice the speed to solve problem. It can be something like you start timer when you start a problem then you have 40-45 min to finish the problem.