Hello, Anyaan

Look JEE mains and advance is conducted every year and each of them has separate reservation and cut-off for different categories.. However, you can check the cut-off based on your category. If you consider the year 2016. For computer science and engineering, the following was the opening and closing rank based on different categories. 

Gen- [24 (opening rank), 186( closing rank)], OBC- [ 33(opening rank), 140( closing rank)], SC-[23(opening rank),  47( closing rank)], ST-[12(opening rank), 46(( closing rank)]   

Now if you consider the year 2017, Following was the opening and closing rank of different categories for computer science.

Gen- [3 (opening rank), 104( closing rank)], OBC- [21(opening rank), 67( closing rank)], SC-[17(opening rank),35( closing rank)], ST-[5(opening rank), 25( closing rank)]   

Now Based this you can get an idea how the seats are going to be filled this year. I hope you find this information useful. Have a great future ahead.