Walmart | Staff | Bengaluru | Rejected

The interview process involved designing a popularity counter with the following functionalities:

• addUser(userId)
• removeUser(userId)
• incrementVote(userId)
• decrementVote(userId)
• getUserWithMostVote()

I initially proposed a brute-force solution using a Map to track vote counts per user and return the userId with the maximum votes. I then suggested using a TreeMap with voteCount as the key and a List of users as values, allowing retrieval of the user(s) with the highest vote count.

However, the interviewer asked for a solution that achieved constant time O(1) for all function calls. I struggled to find an alternative approach even after spending 30-40 minutes.

The interviewer clarified that the internal operations of data structures could be treated as constant, which I found questionable as the time complexity of various internal data structure operations cannot be disregarded.

Observations from the interview:

• Walmart does not utilize coding tests or interview tools like HackerRank or CoderByte for hiring developers.
• The interviewer did not turn on their video but requested the candidate to turn on their video and share their entire screen, not just the active tab.
• My personal opinion is that the interviewer seemed more focused on rejecting candidates rather than evaluating them, potentially providing misleading hints.