A Facebook employee submitted my resume, and I immediately received an email to schedule a technical interview.

I scheduled it two weeks in advance because I had a Google interview scheduled for the following week. The interview questions were easy, and I was able to answer them on time. I had about 10 minutes at the end of the interview to chat with the interviewer. He was pleasant, and we discussed Facebook, its culture, and its technology.

At the end of the interview, he said he was pleased with my responses and would submit his feedback to the recruiter, who would inform me of the next steps.

I was taken aback when, eight days later, I received an email from the recruiter stating they were moving forward with other candidates. I did not receive any feedback whatsoever. I am still trying to figure out where I went wrong.

Q1. Find all the unique characters in a string and return them in place. Example: 'xyxx' should return 'xy'.

Q2. Given a list of unique prime numbers, output all the numbers and all the possible products of 2 numbers and 3 numbers. You cannot multiply a number by itself.