First round was an initial screening which consisted of an aptitude paper and a programming paper. General aptitude paper was not something really difficult. Just to ensure that we can do math, can solve puzzles and understand logic. Programming paper was a C/C++ paper which was again. Brushing up the bit manipulation and pointers would help. Know your OS and Data structure basics. Those who are selected get to the one on one interviews where the first round results are run through again. Plus the you can expect questions on OS, Data structures etc. Interviewers were friendly and helpful. Calm and nice tone.