# C++ Interview with a Meta engineer

#### Watch someone solve the prefix pairs problem in an interview with a Meta engineer and see the feedback their interviewer left them. Explore this problem and others in our library of interview replays.

C++ interview with a Facebook engineer: Prefix pairs - YouTube

[C++ interview with a Facebook engineer: Prefix pairs](https://www.youtube.com/watch?v=fY7k8tsFaFQ)

### Interview Summary

**Problem type**  
Prefix pairs  
**Interview question**  
Given a list of words, match all words with other words from the list that are a prefix for the word.

Read more about the questions
- [Prefix Pairs](/content/questions/prefix-pairs/index.html)

### Interview Feedback

**Feedback about Supreme Beast (the interviewee)**

Advance this person to the next round?
Yes  
How were their technical skills?  
4/4  
How was their problem solving ability?  
3/4  
What about their communication ability?  
4/4

> Interviewee did a great job. Went over the feedback after the interview. Main suggestions are:  
> \* Problem Solving -- Always helpful if you can think of further ways to optimize (reduce iterations to one-pass over trie) that's awesome but definitely not a huge deal. I would still consider this a successful interview.  
> \* Technical Skills/Communication -- To save time during the interview, feel free to skip implementation of some of the helper methods (e.g. get, containsKey) and focus on the core implementation. You can always come back to implementing some of these helpers later.

**Feedback about Mechanical Llama (the interviewer)**

Would you want to work with this person?
Yes  
How excited would you be to work with them?  
4/4  
How good were the questions?  
4/4  
How helpful was your interviewer in guiding you to the solution(s)?  
4/4

### Interview Transcript

Supreme Beast: Hello.  
Mechanical Llama: Hello! Can you hear me okay?  
Supreme Beast: Oh, yeah.  
Mechanical Llama: Okay, great. Nice to meet you. So maybe, before we start, I can just quickly introduce myself. So yeah, so I have been working in industry for, like three and a half years. And I'm a senior machine learning engineer at a big tech company. Yeah. And I'm pretty new to using this platform with this actually being my second interview, but I've been doing interviews at my company for quite some time now. So hopefully, it should be smooth. But I'd love your feedback at the end as well. Yeah, maybe you can introduce yourself to if you want to, you don't have to either.  
Supreme Beast: Yeah, I'm a senior software engineer, working in a machine learning space for more than 10 years. I'm currently interviewing and have some on site schedules and using the site to prepare. I have some interviews already.

... (truncated for length) ...