The rank required to get into Computer Science at IIT Hyderabad varies every year based on various factors such as the difficulty level of the exam, the number of seats available, and the performance of candidates. However, based on previous years' trends, here is an estimate of the rank you should aim for:

• For admission to the Bachelor of Technology (B.Tech) program in Computer Science and Engineering (CSE) at IIT Hyderabad, a rank under 2000 is generally considered a safe bet for General Category candidates.
• However, it is important to note that this is just an estimate, and the cutoff rank may vary from year to year based on various factors.
• The cutoff rank for different categories such as OBC, SC, ST may be different than the General Category.
• It is important to note that the admission to IIT Hyderabad CSE program is based on the Joint Entrance Examination (JEE) Advanced score and rank.
• To get a good rank in JEE Advanced, one needs to have a strong foundation in Physics, Chemistry, and Mathematics and should practice a lot of sample papers and mock tests.
• It is also important to stay updated with the latest syllabus and exam pattern and prepare a solid study plan with dedicated time for each subject.
• It is advisable to start preparing for JEE Advanced well in advance and take guidance from experienced teachers or coaching institutes.

In conclusion, to get admission to Computer Science at IIT Hyderabad, one should aim for a rank under 2000 in JEE Advanced. However, the cutoff rank may vary from year to year, and it is important to stay updated with the latest trends and prepare well for the exam.

Due to the increased demand for specialization, many students can be found transferring their branches to Artificial Intelligence departments since those provide better placement opportunities and high salary packages. 

There is no specific CGPA requirement needed for a branch change. However, in accordance with the branch change policy, no department can take more than 10 % of its current number of students through the provision of Branch Change. So a branch that has 50 students can only admit 5 top students from other branches. 

Hence it can be concluded that there is no specific CGPA required for branch change. It all depends on the competition between the students. However, based on one of my friends' experiences, the approximate CGPA required for branch change to AI or CS is around 9.6-9.8 in the first semester. Please note that this is just an approximate figure as there are no fixed criteria.