Google Phone Screen L3 - USA - Rejected
- Result
- Rejected
- Location
- USA
- Posted
- 4 Sept 2025
Summary
I had a phone screen for an L3 role at Google in the USA where I was presented with a problem involving mapping IP addresses to their most specific prefix, which I failed to solve, leading to my rejection.
How it went
I recently had a phone screen interview for an L3 position at Google in the USA. The interview focused entirely on a single coding problem. I was given a task to map IP addresses to their corresponding prefixes based on a given list of prefix rules. I struggled significantly with the problem, failing to identify the correct data structure and approach, and ultimately couldn't come up with a working solution. This directly led to my rejection from the role.
Questions asked (1)
- 01
Map IP Address to Most Specific Prefix
Data Structures & Algorithms
Given a set of IP prefixes and a set of IP addresses, map each IP address to its most specific matching prefix. If no specific prefix exists for an IP address, it should be mapped to the wildcard prefix '*'.
Prefix examples provided:*192.168.*192.168.2.*192.168.2.1
0.0.0.0192.168.7.1192.168.2.3192.168.2.1
0.0.0.0 → *192.168.7.1 → 192.168.*192.168.2.3 → 192.168.2.*192.168.2.1 → 192.168.2.1