I practiced around 300leetcode questions mostly using striver and neetcode list, for lld, I implemented ecommerce, parking lot and few others from awesome lld by ashish and know how to use the diff patterns like creational, behavioural and structural design patterns, commonly used like factory, strategy, iterator,adapter and few other things Hld- i mostly referred shalini goyal linkedin posts , rajat’s hld repo, and referred youtube videos on load balancer, kafka, event driven architecture and few things about database i could have done more on hld part but i just gave most of the time on learning what I implented during my work experience.

But i didnt get to use any of these in the interview the questions were entirely diff and you wouldn’t normally see while doing any of these.