Hello Raj,

Well you cant get Computer Science branch through your JEE Mains B.Arch percentile. JEE Mains paper 2  is only for architecture and one has to also clear NATA if he/she want to go for a career in architecture. So now lets talk about your WBJEE rank. As per your 2019 WBJEE rank, you wont get a seat in the top institutes for CSE like Jadavpur University and all. The cutoff varies from one college to another and also on the basis of category. Below I have listed some of the colleges under WBJEE where you might be able to get a seat for CSE - 

• Heritage Institute of Technology
• Narula Institute of Technology
• Academy of Technolgy
• Bengal Institute of Technology
• Haldia Institute of Technology
• Kalyani Government Engineering College 
• Jalpaiguri Government Engineering College
• Techno India University

You can also go through this link and checkout the detailed previous year cutoff for the colleges under WBJEE along with category wise ranks : https://engineering.careers360.com/articles/wbjee-cutoff

Hope you get your choice of branch and college. Good Luck !!!