Facebook | Phone | Mismatched sentences & Fill an Array
I've gotten a lot from this community and want to give back. These are questions from my phone screen, for a data engineering role. The key to my success was thinking out loud, to give the interviewer insight into my thought process as I coded.
Also! When I got stuck on special cases (e.g., syntax stuff I'd ordinarily Google), I wasn't scared to ask the interviewer for help... for example, I wasn't sure if .split() happened in place or if I needed to create a new object to store the result, and I just asked.
(Python Q) Mismatched sentences
Write a function to identify the words that appear in one sentence but not the other (case sensitive).
Example
- string 1:
"This is the first sentence" - string 2:
"And this is the second sentence" - output:
['This', 'first', 'And', 'this', 'second']
(Python Q) Fill an Array
Given an array with 'empty' spots, fill those empty spots with the preceding number.
Example
- input array =
[8, None, 3] - output array:
[8, 8, 3]
SQL Qs
For the SQL portion, I was given a database schema and asked to calculate ratios from the provided four tables. I wasn't given any details on the contents of the tables, besides a listing of their column names. I was just left to ask questions about what I needed. Themes throughout my solutions:
- use of
WHEREstatements to filter (and wildcard characters to filter string-valued fields) - ordering results by the output of an aggregation function
- using
JOINs to pull together multiple tables (e.g., numerator in one table and denominator in another)


