Google SDE 1 Onsite: Word Ladder Reachability and Typing-Distance Problems

GoogleSoftware Engineer, SDE 1·Not specified·Interviewed May 2020Outcome unknown

Updated July 17, 2026

This account comes from a candidate who ran interview loops with both Microsoft and Google around the same time and wrote up the experience for the LeetCode Discuss community. The Google portion covers an SDE 1 onsite loop; the candidate did not describe earlier stages (recruiter screen, online assessment) for the Google process specifically, so this write-up focuses on the two onsite technical rounds that were detailed.

Both rounds leaned on core data-structure and algorithm reasoning rather than open-ended system design. The first round asked the candidate to reason about word transformations as a reachability problem; the second bundled two separate, unrelated problems into a single session. No final outcome for the Google process was mentioned in the original post.

How the process went

Context
The candidate had recently interviewed with both Microsoft and Google and wrote up both experiences together; only the onsite technical rounds for Google were described in detail.
Onsite Round 1
A single problem centered on reachability between words in a given dictionary, where transitions add or remove one character at a time.
Onsite Round 2
Two separate problems in one session: a grid-based typing-distance optimization and a set-outlier detection problem.
Outcome
The post does not state a final decision for the Google process; the candidate's confirmed offer in the same write-up was from the separate Microsoft loop, not Google.

Onsite Technical Round 1

Reachability over word transformations (graph/BFS-style reasoning)

Given a dictionary of words, determine whether you can go from a given start word to a given end word such that every intermediate word along the way also exists in the dictionary, where a transition either adds a character anywhere in the word or removes a character from anywhere in the word.

The candidate illustrated the idea with a small example dictionary showing a valid chain from a short start word to a longer end word.

Onsite Technical Round 2

Two independent problems: keyboard-distance optimization and outlier-set detection

Given letters arranged in order across a small grid (rows of 9, 9, and 8 characters) and a target string, find the minimum total finger-travel distance needed to type every character in the string using two fingers, where both fingers may start at any position and the goal is to minimize total movement.
Given an array of character sets, find the longest set that does not intersect with any other set in the array, without relying on a built-in set-intersection method.

The candidate noted the typing-distance question resembled a known two-finger typing distance problem and flagged the outlier-set question as requiring a manual intersection check rather than a library call.

Key takeaways

Practice reframing word-transformation or dictionary-lookup problems as graph reachability (BFS or similar traversal) rather than treating them as pure string manipulation.
Review grid- and distance-optimization problems where movement can start from any position, since the same underlying two-pointer or DP idea shows up across different surface setups.
When a problem restricts a built-in method (like set intersection), be ready to explain and implement the equivalent logic manually rather than relying on library calls.
In back-to-back rounds covering unrelated problems, keep track of which constraints apply to which question so you don't mix up assumptions under time pressure.
Write down your own round-by-round notes soon after interviewing, since details across multiple company loops can blur together quickly.

Source

The questions and process facts come from the candidate's public write-up, linked below. The retelling above is our own summary.

Candidate's public write-up on LeetCode Discuss