Software Engineer · Onsite · Coding

Google — Software Engineer

Level: Senior-Level

Round: Onsite · Type: Coding · Difficulty: 6/10 · Duration: 120 min · Interviewer: Friendly

Topics: Arrays, Strings, Hash Maps, ASCII, Data Structures, Linked Lists

Location: San Francisco Bay Area

Interview date: 2026-02-10

Summary

Round 1: Coding

Question: Given an array of strings, group the strings based on the distance between each character in the string.

Round 2: Coding

Question: Implement a restaurant waitlist with add to waitlist and allocate table functionalities.

Details

Round 1:

I was given an array of strings and had to group them based on the distance between each character. The distance is the relative distance between characters (e.g., 'b' - 'a' = 1). I was a bit nervous at first and didn't ask about edge cases immediately. I used a map to store the groupings and output the values. I made a mistake initially by trying to store the string as the key and the distance as the value, but the interviewer corrected me. I also forgot how to get the ASCII value of a character in Python and initially wrote s[i] - s[i-1] before the interviewer reminded me to use ord(). I even wrote ord(s[i] - s[i-1]) incorrectly at first. I handled edge cases like 'z' - 'a' by using mod 26, which the interviewer said was fine. Only at the end did the interviewer mention that the strings weren't limited to lowercase, which threw me off, but mod 52 would work for uppercase as well.

Round 2:

I had to implement a restaurant waitlist with add_wl and allocate_table functions. I used a map, deque, and set. The interviewer said it was a decent solution. The follow-up involved allowing table allocation to search for the first person in line from all tables smaller than the current size. The interviewer's description was vague, and I had to ask clarifying questions. The interviewer described a solution involving O(n) traversal, but I was trying to come up with an O(1) solution. I don't know how well the follow-up went. After the interview, I realized my map, deque, and set solution had vulnerabilities and that a linked list would be better. However, the interviewer didn't mention this during the interview.

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