Google Phone Screen Interview Experience (45 mins)

Time Breakdown:

• Interview Duration: 45 minutes
• Interviewer Delay: Joined 4 minutes late
• Introductions: ~5-6 minutes
• Asking questions at end: ~3-4 minutes.

So roughly I left with only 30 mins

Technical Question 1:

Problem:
Given a list of integers, find the length of the largest non-decreasing subarray.

My Approach:

• Clarified the problem with a couple of follow-up questions.
• Proposed an O(n) optimal solution using the two-pointer technique.
• Walked through the approach with a concrete example, as requested.
• Implemented the code and explained it line-by-line using the same example.

Follow-up:
What unit tests would you write for this implementation?

My Response:

• Test with a strictly increasing array.
• Test with a strictly decreasing array.
• Test with a mixed array (increasing and decreasing segments).

Follow-up Question 2 (Advanced Variant):
You are allowed to flip one number in the list (i.e., change it to any value). Now find the length of the largest non-decreasing subarray.

My Thought Process:

• Took ~1-2 minute to think.

• Initially proposed a more complex solution.

• Quickly realized the overcomplication and pivoted to a simplified O(n) approach using 3 pointer approach kinda ,but I didn't get chance to implement or dry run it with example(but the approach was right as I later verified using chatGPT post interview).

• Only ~3 minutes remained by the time I reached the optimal solution.

• Interviewer acknowledged he got the gist of my approach and wrapped up with a polite “Best of luck for the upcoming interview rounds.”

After few days I came to know from recruiter that I didn't get positive feedback and I got feedback that I need to work more on DSA.

I would like to know what is the general expectation in the google phone screen round and where I could have done better?

Thanks :)