Facebook Intern 1st Interview


  • Duration: About 45 minutes
  • Questions: 3 if counting with the ones that I already knew


  1. Serialize and Deserialize a Binary Tree
    I already knew this question, so I told him and he asked me to explain my solution, so I did and he accepted and moved to the next one.
  2. Lowest Common Ansestor
    I also did this question before, so I did like the previously one
  3. Smallest Subtree With Deepest Nodes
    This one I didn’t solve before, so I started with an idea, but I didn’t understand the whole output, so I was a little bit confused until ~40 mins of my interview but, at the end, I asked about the inputs and he corrected me, so I was able to solve it quickly and explain the space and time complexities.


I was able to move to the second interview even thinking that I went realy bad on this one. So don’t be afraid about getting the best solution quickly. Discuss your solution with him and he’ll help you to get there :slight_smile: