Dear Aspirant ,

First of all you need to know what subjects are required to prepare for IAS exam in both prelims and mains !

In prelims you will have to papers based on General Studies and aptitudes .

In mains , you will have total nine  papers including compulsory Indian Language,English, Essay , General Studies (4 papers) and optional subject(2 papers). In optional subject , you need to choose your preferable subject from their selected lists !

But I'm sorry to say , computer science is not included in that optional list ! So you need to choose another subject with which you will be comfortable to prepare !!

Here is the reference for you about IAS and their syllabus , just go through this :

https://competition.careers360.com/exams/upsc-civil-services-exam

Hope it helps !

Best wishes !!