Google ML Campus New Grad Phone Screen: Shortest Path and Maximum-Clearance Follow-Up

Role: Machine Learning Engineer / SWE, PhD New Grad
Result: Passed the phone screen
Report time: April 2025
Application: Referral

Timeline

• February 5: applied with a referral
• February 10: received the OA
• Roughly two weeks later: received phone-screen outreach
• About one week after submitting availability: interview scheduled

Base problem: shortest land path

An m × n matrix contains walls 0 and traversable cells 1. Given start and target cells, return a shortest valid path.

Practice: Shortest Land Path

Follow-up: maximize clearance from another point

A third point C is added. Among all start-to-target paths—not only shortest paths—maximize the minimum Euclidean distance from any point on the path to C.

For each path, compute its closest pointwise distance to C; then choose the path whose closest distance is largest.

The candidate later proposed binary-searching a clearance threshold and checking whether a path exists using only cells meeting that threshold. Commenters also described a max-priority-queue widest-path formulation.

Practice: Maximum-Clearance Path From a Point

Coding was written in Google Docs, and no additional nontechnical question was asked in that round.