IIIT Delhi is clearly the best choice out of the three options especially if we are talking about CSE. Your preference order should be the following.

IIIT Delhi (Indraprastha) > Thapar University > LNMIIT Jaipur

Cutoff: (IIIT D > Thapar University)

The quality of the students also has an effect on how the college performs and also in its rankings. The cutoff for CSE at IIIT Delhi is around 200-225+. Thapar University admits students with JEE Mains marks more than 170 for students’ outside Punjab and 150 marks for students from Punjab. The cutoff indicates IIIT D offers a better peer group. 

Placements: 

• In terms of placements and internships, IIIT Delhi tops the list. The avg. package for the CSE branch in IIIT Delhi is around 15 lakhs per annum. 
• Overall avg package in Thapar University is around 8 lakhs per annum and for CSE Branch is around 10 lakhs per annum with a placement rate of 94 percent. 
• In LNMIIT Jaipur the avg packages are around 6 lakhs per annum. 

Thpar has a great coding culture. However, based on student crowd, placements, etc. the best option among the given choices is IIITD.