The Leetcode Order (Free PDF)
This PDF is the list of problems to do, grouped by topic, in order. Each topic builds on the one before it, so start at the top and work down. Every problem links straight to LeetCode.
How to use it:
Try each problem for 20 to 30 minutes, closed book.
If you can't solve it, look at the solution and make sure you understand it. Videos and AI are fine for this.
Retry the problem on your own another day.