Hello Codeforces community,I have recently started participating in contests. Before that, I was just solving the A2oj ladder problems to get familiarised with Problem levels A, B, C, D. Now what I have seen in my case is that sometimes during virtual contests or in contests as well, I get stuck in problem level A as well.

So I would like to know if this happens with experienced coders as well? Also what do you think is the best approach to improve, whether I should focus more solving many more A and B problems until I become good enough to not get stuck on these, or should I continue practising C and D levels as well, hoping that the improvement in C and D will help with A and B as well. I mean should the approach be Breadth First where I become very good at A, then B, then C and so on or should it be Depth First, where I upsolve C and D as well and keep practising all types equally.