The interview process was pretty smooth and quick.

I received a call from the recruiter, and first had to submit a code sample of any project I had worked on.

Then, there was one online coding test and two live coding interviews over the phone.

I did not have any on-site interviews.

An array has negative and positive numbers. Separate the numbers such that negative numbers are at the beginning and positive numbers at the end, without changing their original order. You cannot sort the array.

Explain with O(1) space.