4 years mathematics and computing at IIT Ropar is better because I would suggest you to always opt for four years course rather than 5 Year course until you are hundred percent sure that you are interested in that subject and you want to make future in that subject is specifically if you choose applied mathematics then it is much related to research and science purpose and not job oriented so if you are targeting for getting a placement and then you should go for mathematics and computing at IIT Ropar apart from that if you are getting some good 4 year course at IIT Roorkee then you can choose that because IIT Roorkee is much better compared to IIT Ropar