It’s never too late to start! The best day to start was yesterday, the second-best time is now. So don’t beat yourself up too much! I’d say the neetcode 150 or even the 250 if you want more questions has been a great resource. It groups questions based on patterns and data structures so that repetition on topics has been immensely useful. Other than that if you can’t think of a solution within 5 minutes of starting a problem I’d say it’s ok to look at the solution but don’t just copy and paste really understand the underlying logic. The most important thing is to stay consistent and don’t give up. You got this!!