Facebook 2019 Intern Phone Interview Round1(Fail)

Your current employment status, work experience and the position you are interviewing for:
Status: MS student, graduating in less than 1 year.
Position: Intern
Location: Seattle, WA
Date: applied Aug 21th 2018, phone interviewed at Oct 18th 2018 and failed.

The interview process:
Two questions, easy + regular hard, all tag questions with slightly variation, e.g. input and output type

  1. https://leetcode.com/problems/binary-tree-paths
  2. https://leetcode.com/problems/minimum-window-substring

I solved the problems, but I made mistakes on time and space complexity analysis for the first problem.I gave an answer without consideration, which is really bad. Even I corrected myself later, I still failed. Since I was lacking of interview experience, my explanation seemed unsure, which gave the interviewer a bad impression.

Your thoughts and anything else you’d like to add, e.g. culture, office, perks, lunch, accommodations, etc:

  1. First and for most, apply early. I often hear people saying that Facebook has a respectively restirct diversity hiring rule that will give quote to different schools. From my experience, my classmates who applied later have a less change to get the interview opportunities, but it is not all the cases.
  2. From my interview experience, I think Facebook likes optimal solution and expect interviewee to solve the problem fast and clear. The questions are normally tag questions, but the standard is higher. And sometimes the interviewer doesn’t want to discuss with you. So we need to have the ability to give them optimal solution fast. So we need to practice.
  3. Time and space complexity analysis is so important.
  4. Conficence is vital for your interview’s success.