Machine codingService designCorrectness & scale

Google India-Style Machine Coding Round: Format, Tips & Practice Problems

Written and reviewed by Sahil Srivastav

Infrastructure-flavoured product problems reward a precise contract more than a large framework. Rounds in the style of Google India often turn indexing, quotas, scheduling, caching, or dependency processing into a small implementation whose edge cases expose the model.

This page is a style guide with Gronex originals. It emphasises a testable core and clear discussion of how the design would grow.

What a Google India-style machine coding round looks like

Expect a scoped build in which inputs arrive over time and the service must return deterministic results: a scheduler, cache, rate limiter, dependency resolver, or quota manager.

The follow-up usually changes one constraint—fairness, expiry, duplicate work, or a new priority. A clean policy seam and explicit data invariants let you extend without rewriting the core.

Infrastructure discussion belongs after the demo. Explain memory, complexity, failure, and persistence trade-offs from the behaviour you have already implemented.

How you’re evaluated

Contract precision

Inputs, outputs, errors, and boundary cases are explicit.

Deterministic behaviour

Equal-priority work and expiry decisions have stable ordering.

Complexity awareness

The chosen data structures match the access pattern and stated limits.

Failure handling

Retries, expiry, and partial dependency results have defined outcomes.

Common mistakes that fail this round

  • Starting with a distributed architecture before implementing the local contract.
  • Leaving tie-breaking and expiry semantics unspecified.
  • Using a linear scan where the operation is repeatedly called under a stated limit.
  • Mixing time access into business logic.
  • Claiming exactly-once behaviour without an ownership or deduplication mechanism.

Quick tips for the room

  • State complexity before choosing structures.
  • Inject time.
  • Define tie-breaking in one place.
  • Keep the first implementation small and observable.

How to prepare

Practise one scheduler and one cache or quota problem with a written complexity target.

Read the failing tests in the repositories below as contracts, then explain which production primitive would preserve each invariant.

Practice problems in the Google India-style round format

Each is a real backend repository with a failing test suite — the same working-code standard the round applies. Open the brief and read the full problem, no signup required.

HARD~90 min

Distributed Job Scheduler

Schedule work and prevent duplicate execution.

Open the challenge →
MEDIUMFree~75 min

Sliding Window Rate Limiter

Enforce quotas at precise boundaries. Free to try.

Open the challenge →
MEDIUM~90 min

LRU Cache with TTL & Statistics

Eviction, expiry, and observable cache counters.

Open the challenge →
HARD~105 min

Dependency-Aware Task Execution

Run a graph of tasks with failure propagation.

Open the challenge →
HARDFree~90 min

Duplicate Side Effects

Deduplicate effects under replay. Free to try.

Open the challenge →

Rehearse the round before you sit it

Open a real repository, see the failing tests, and make them pass against the clock — the loop a Google India-style machine coding round actually grades. Start free, no card required.

FAQ

Were these Google India questions?

No. They are Gronex originals in the style of infrastructure and service-design rounds. Gronex is not affiliated with Google.

Should I optimise immediately?

Meet the contract first, then name the access pattern and improve the structure where the stated workload requires it.

How much distributed design is expected?

Explain the production boundary after the local implementation demonstrates the invariant.

What is a strong demo?

A short happy path followed by one boundary and one failure case, with outputs that make the contract visible.

Related

Gronex is not affiliated with, endorsed by, or sponsored by Google India. All company names and trademarks belong to their respective owners. The problems on this page are Gronex originals written in the style of such interview rounds — not actual interview questions from Google India.