Google New Grad Onsite Rejection: Hash-Chain List, Prefix Counts, and Grid Paths

Role: Software Engineer, New Grad
Result: Rejected after the onsite
Report time: October 2024

Coding round 1: head-inserted hash chain

Implement a secure linked list with head insertion. Every node's stored hash combines the hash of its own value with the next node's hash.

Practice: Head-Inserted Linked-List Hash Chain

Coding round 2: prefix counts in sorted words

Given a sorted string array and a prefix, return how many words begin with that prefix. The candidate used binary search.

Practice: Count Prefix Matches in a Sorted Array

Behavioral round

The candidate said the discussion went reasonably well but did not preserve the individual questions.

Coding round 4: grid paths with obstacles

The base problem was LeetCode 62, Unique Paths. The follow-up added obstacles and asked for the number of paths that pass through all obstacles.

That wording conflicts with ordinary blocked-cell semantics and was never clarified in comments. It is unclear whether “obstacles” were required checkpoints, removable blocks, or another object, so no exact follow-up link is asserted.

The candidate completed the questions with some hints but believed the first two rounds were too slow to reach enough follow-ups. The rejection arrived nine days later.