In selection process there were two stages... !st one was Written test which consisted two papers.
1st- picture series questions. total 36 questions nd time allotted 36 minutes.most ques were from R.S.Agarawal
2nd- technical ques like program output, quantitative aptitude ques, antonyms, synonyms, fill in the blanks , relation type ques... logic reasoning..,english passage.total 38 ques 30 mins alloted...

it was an tech cum HR round...mine interviewer was a great man..he was a political maniac too.starting from tell me about urself to who is the chief minister of mp..
i don't remember the sequence but the ques were.
tell me about urself, family background
why computer science,
some political ques like who is pm,cm president etc,
i told him that i like maths then fired some of maths ques like wt is nelson number, wt is ramanujan number, wt is armstrong number with examples...
he asked me abt my hobbies, wt i did great and feel proud .
trignometry ratios and proof,my rank in aieee and score in iit-jee
some basic concepts of oops and c
he asked me abt my final year project
why i willing to join niit-tech etc

for niit-tech...prepare R.S.Agrawal, most ques were from there only.
reasoning ques and aptitude ques all were from those two books.
some programming ques like output... only basics..some basics of dbms, data structure and oops these were the areas where technical ques were asked.just be confident on them..

for interview the key fact is prepare ur resume well and stick to that..whatever u write in ur resume u should know well. be confident...these guy are very friendly.....they will always encourage you.

total applied students were 80 out of which 40 selected for HR/Tech round.
and finally 18 students were selected.mine was 9th rank......when successful candidates name were announced
yup,,good gpa was one of the reason, and i can say that..he was great guy who loves maths and politics...and i was very gud answering those ques.
also i can say luck was in my favour thats why he asked me ques from politics and the subject i like most...