Pinterest Software Engineer Interview Experience — Three Parts Passed Before Time Ran Out

The phone screen used the familiar Pins Violation Log problem.

The input was a list of violation logs already sorted by timestamp. Each record had the form [postId, policy, timestamp]. There were five parts:

1. Count unique posts by policy.
2. Get the policies violated by a post.
3. Count unique posts at a timestamp.
4. Count unique posts in a time range.
5. Count violations by policy in a time range.

I had to run test cases during the interview. I first explained my approach for each part, and once the interviewer confirmed it, I started writing code. I completed the first three parts and got their tests to pass. For the fourth and fifth parts, I explained the solutions clearly, but I ran out of time before I could finish implementing them.

Given Pinterest's bar, I think I probably failed.