My rank is 20k and i am from obc category. I have also passed the qualifying marks, will i get cse branch in any top engineering colleges?

You can get CSE but not in top colleges. For CSE you have to apply for your domicile government colleges or private institute through counseling.
If you want to join in top colleges then you have to choose mechanical engineering or civil engineering. Or biotech engineering.
You can use the college predictor to get list of colleges you can take an admission with respect to your entrance.
For an information, every college is good. Even the private colleges.
It's my experience. So choose one as per your choice and interest.
Good luck!

Hello aspirant!!
Your query is incomplete. Please mention the entrance exam in which you got 20000 rank. If you mention the entrance exam name then I could help you out with your query. Actually your query requires the entrance exam name.
So please provide me with the entrance exam name.
Thank you :)