It was a very well-organized process. One telephonic interview, of about 45 minutes, covered a couple of data structures questions and my graduate projects. It went very well.

After this interview, I was called for an onsite interview, which included four face-to-face interviews and one with the hiring manager.

Interviewers were good. They asked mostly data structures and algorithms questions, not too difficult. Everyone asked me to code, which I did really well. One interviewer asked me to just discuss the solutions and not to code; we discussed three to four data structure questions deeply.

The only part that didn't go well was the hiring manager interview. We discussed mostly my graduate projects, and he was expecting something specific from me, which I didn't quite grasp until the end.

Overall, it was a good experience. Although I did not get an offer, I thought it was very close. They replied to me within a week. It is a very good company, and I would like to reapply.

1. Check whether the tree is a binary tree or not.
2. Find numbers in monotonically increasing and decreasing number sequences.
3. Given an array, find two numbers that sum up to a third number.
   • In O(n) time with O(n) space.
   • In O(n log n) time with constant space.
4. Given an expression with only '+' and '*' operators and operands, solve the equation in O(n) time.