I was contacted by a Facebook recruiter in Australia for a US position.

I was scheduled for a video call round within two weeks. The interviewer was from the Instagram team.

Five minutes of introduction was followed by two data-structure questions for thirty minutes. I solved both questions and wrote error-free code.

After the interview, when I checked my solutions, my first algorithm was good, but the second one was not the most optimized. I guess that's where it didn't work out well.

Find the maximum sum of all elements of an array where no two adjacent elements are considered.

Find the rightmost and leftmost occurrences of a number in a sorted array.