Single Element Among Pairs

An easy Python mock interview question on DataDriven, with an AI interviewer who asks follow-up questions and a hire or no-hire decision at the end.

Domain
Python
Difficulty
easy
Seniority
L4

Interview Prompt

Our replicated log writes every event id twice, but one id was written only once. Given the ids in the log, return that id.

Summary

One element has no partner.

How This Interview Works

  1. Read the vague prompt (just like a real interview)
  2. Ask clarifying questions to the AI interviewer
  3. Write and run your Python against test cases
  4. Answer the interviewer's follow-up questions, then get a hire or no-hire decision