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PayU Worst Interview Experience | SSE | Bangalore | Awaiting

Round 1: Problem Solving/Data Structures

Questions:

  1. Increasing Triplet Subsequence:

    • I initially proposed an O(n^3) solution and then optimized it to O(n). I discussed the approach with the interviewer, who then asked me to code it on Google Docs. After completing the code, we dry ran it on a few test cases. The interviewer then pointed out that my implementation was incorrect because it didn't maintain a, b, c explicitly. I tried to explain that the problem only required a boolean return value, but he disagreed. With 15 minutes left, he moved on to the next question without letting me finish discussing the first one.
  2. Maximum Number of Vowels in a Substring of Given Length:

    • I solved this question optimally using a sliding window approach on the first attempt. The interviewer asked for the time and space complexity. I explained that it was O(n), but he insisted it should be O(n^2) because of the use of two loops. Despite my efforts to clarify that the worst-case scenario involves iterating over the entire array twice, he didn’t understand and abruptly ended the interview.
Candidate's Approach
  • For the first question, I proposed an O(n^3) solution and optimized it to O(n) through discussion.
  • For the second question, I effectively used a sliding window approach to achieve an optimal solution.
Interviewer's Feedback
  • The interviewer pointed out issues with my implementation of the first question and insisted on a different interpretation of the time complexity for the second question, leading to an abrupt end of the interview.