I am interested in programming, algorithms, etc. So what will be good for me: IIIT-Allahabad IT or IIIT-Delhi CSE?

 If you are given a choice between IIITA and IIITD, take admission in IIIT Delhi hands down. You will never regret it. IIIT Delhi has everything that a good IT institution needs i.e. Great faculty, excellent domestic and international placements, and an overall great experience.

IIIT DELHI

The cut-off for admission at IIITD ranges from 16694-28261. IIITD has a great set of faculty members and the curriculum is excellent.IIITD lacks diversity. With around 85% of the student community belonging to Delhi, it isn't catering to a pan-Indian audience. IIIT-Delhi students seemed frustrated with the workload and students are left with deadlines every single day and thus have no life out of academics. 

IIIT Allahabad

The candidate must have cleared the JEE Mains. The cut off for admission at IIITA ranges from 1291-5330. IIITA has a great coding environment. Faculty is not up to the mark.

They both have a good curriculum but IIIT Delhi has so much more to offer. So If I were you, I would definitely choose IIITD.