The interview process is moderately tough. The interview is completely oriented towards problem-solving questions only, with no technology-related questions. They expect you to write the code for the problem, keeping all testing angles in mind. In short, the code should be runnable and productizable as is.

The interview email clearly states what they are looking for in a candidate. I followed their instructions very religiously, and I felt it helped me a lot to get an offer.

For example, they say, "Don't assume things, ask questions when not clear." This happened to me during the interview. Initially, they ask questions with less clarity, so here you need to bring out all the assumptions you are making, etc. You can even ask for hints if required; they will help you.

Basically, their goal is to understand if this person is thinking in the right direction and, with a little help, is able to solve problems.

How do you test a telephone?