most of the leetcode problems are based on material that a new grad CS major would have learned recently from taking a class that uses CLRS as the textbook. if this background is assumed then the key to success becomes building problem solving skills.
if you haven't very recently taken a class that uses CLRS as the textbook, then it makes sense you would have to do more memorization and practice with those concepts.
if you haven't very recently taken a class that uses CLRS as the textbook, then it makes sense you would have to do more memorization and practice with those concepts.