Google L3 software engineer interview: phone screen, four coding rounds, and the Googleyness round

GoogleL3 Software Engineer·Bangalore, IN·Interviewed June 2020Offer

Updated July 16, 2026

This account covers the full Google entry-level loop: recruiter contact through LinkedIn in late March 2020, a phone screen in late April, virtual onsite in mid-June, then a separate Googleyness round before the offer in July. Google gave prep time at each stage when asked — two weeks before the phone screen, a month before the onsite.

The most instructive part is round three of the onsite. The candidate reached the optimal solution quickly, and instead of moving on, the interviewer spent the remaining 25 minutes pushing past it: if the optimal algorithm is too slow for a large-scale system, what approximate answer can you compute in linear time? It took six or seven progressively better proposals before the interviewer was satisfied. Finishing the problem is where that round started, not where it ended.

How the process went

Recruiter outreach
Contacted through LinkedIn in late March 2020; process kicked off in early April with two weeks granted to prepare.
Phone screen
45 minutes in late April after two reschedules. One array problem in two parts — a straightforward implementation, then a variant requiring binary search — followed by complexity analysis and the candidate writing out about ten test scenarios.
Virtual onsite
Mid-June: four 45-minute technical rounds, coding done in a shared doc.
Googleyness round
Scheduled after strong coding feedback; behavioral and hypothetical situation questions. The candidate asked for and got a week to prepare.
Decision
Offer in July 2020, roughly four months after first contact.

Technical round 1

Coding — binary trees · 45 min

Two medium binary-tree problems back to back.

The candidate spent the first five minutes restating the problem in their own words before proposing an approach — a rhythm they kept all day: rephrase, propose, get agreement, code, then walk the code against sample inputs hunting for off-by-one errors.

Technical round 2

Coding — DP + class design · 45 min

A medium problem where the candidate offered two or three approaches and was asked to code the dynamic-programming one.
Design and implement several methods of a class; the clean solution needed a heap / priority queue.

Offering multiple approaches and letting the interviewer choose worked well here — both problems were done with time to spare, and the recruiter later flagged this round's feedback as particularly strong.

Technical round 3

Coding + scale follow-ups · 45 min

One binary-tree problem, solved and optimized quickly.
Follow-up chain: the optimal solution is quadratic — for a large-scale system, produce an approximate/heuristic answer in linear time.

The follow-up chain ran about 25 minutes and six or seven iterations, each proposal improving accuracy over the last, until the interviewer accepted the trade-off. The candidate needed a hint on the (non-trivial) complexity analysis earlier in the round — that didn't sink it. What mattered was iterating in dialogue rather than defending a first answer.

Technical round 4

Coding — trees + strings · 45 min

For every node in a binary tree, check whether the absolute difference between the left-subtree sum and right-subtree sum satisfies a given condition (linear recursive solution).
A medium string problem checking whether an answer exists, with a follow-up to construct one possible answer (discussed via a linked-list approach, not coded).

Counter-questions on the approach were resolved by working the approach on concrete examples in front of the interviewer rather than arguing it abstractly.

Googleyness

Behavioral + hypothetical situations · 45 min

Tell me about a time you contributed to the team's success.
Tell me about a time you failed to deliver a project — what did you learn?
Tell me about a time you showed leadership without being the official leader.

The candidate prepared distinct stories per question, studied Google's stated values, and treated this round as seriously as the coding — it comes after the technical feedback but is a real gate, not a formality.

Key takeaways

Ask for prep time — this candidate got two weeks before the phone screen and a month before the onsite just by asking.
Practice coding in a plain shared doc if that's the interview medium; the candidate drilled this until doc-written code compiled cleanly when pasted out.
Reaching the optimal solution can be the midpoint of a round. Be ready for "now make it work at scale" follow-ups where the answer is an engineering trade-off, not a textbook algorithm.
Trees dominated this particular loop — three of four coding rounds featured binary trees — but the transferable skill was the loop of restating, proposing, confirming, then coding.
Prep volume: about 125 problems in two weeks for the phone screen, then around 300 more over two months for the onsite, plus mock interviews.

Practice a Google interview

Rehearse out loud against the kinds of questions in this story — with an AI interviewer that asks follow-ups.

Practice this interview

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