I seem to have encountered some obstacles in my study of informatics competitions, so I am posting this to seek your help:

I can now solve problems with a difficulty level of AC 2100~2200 relatively quickly, but for those with a difficulty level of 2300~2500, I can only come up with partial solutions for most of them, and rarely manage to solve them directly. Moreover, I seem to struggle with prolonged thinking. If I can't solve a problem directly, it's unlikely that I'll be able to do so through more contemplation. And often, my approach is similar to the correct solution, but there are always some deviations. What can I do about it?

And in different areas, for example, my data structure skills are relatively good while my DP skills are relatively poor. Could anyone give me some advice? Thank you!