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Google·Software Engineer·Onsite - Coding / Algorithms·Intermediate

IntermediatePrefer not to say
Jul 2026

Summary

Google SWE interview with a simulation-style coding problem involving feature activation and dependency management. The problem statement was incomplete or partially abstracted, which made it genuinely hard to know what was actually being asked.

Questions Asked (1)

Q1

Given a system with n features and a set of dependency relationships between them, simulate a sequence of activation requests. Determine whether each activation succeeds, what side effects occur, and what the final state of the system looks like.

Algorithms & Data StructuresSystem DesignAdaptability & Ambiguity
Author's notes

The problem description was half-missing, which honestly made this more stressful than the actual algorithmic content.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the problem: define what activation means, how dependencies affect activation, and what side effects are expected. Then model the system as a directed graph and simulate each request using appropriate traversal and state tracking. Finally, summarize the final state and discuss edge cases and optimizations.

Pro tip: Explicitly state your assumptions about dependency semantics (e.g., whether activation requires all dependencies to be active) and side effects (e.g., cascading activations). This shows you can handle ambiguity and design robust solutions.

1. Clarify Requirements and Assumptions

Ask questions to understand what 'activation' means, how dependencies influence it, what side effects can occur, and what the initial state is. Confirm whether dependencies are prerequisites or just relationships.

2. Model the System

Represent features as nodes and dependencies as directed edges in a graph. Choose appropriate data structures (e.g., adjacency list) and define state variables (e.g., active/inactive, pending).

3. Design Simulation Algorithm

For each activation request, check if prerequisites are met. If so, activate the feature and propagate side effects (e.g., activate dependents). Use BFS/DFS or topological ordering to handle cascades.

4. Handle Edge Cases and Optimizations

Consider cycles, already active features, failed activations, and concurrent requests. Discuss time/space complexity and possible optimizations like memoization or incremental updates.

5. Summarize and Validate

After processing all requests, report the final state of each feature and any side effects. Walk through a small example to validate the approach and ensure correctness.

Key Points to Mention

  • Graph representation of features and dependencies (directed graph, adjacency list)
  • Activation conditions: whether all dependencies must be active or any (AND/OR semantics)
  • Side effects: cascading activations, notifications, or state changes
  • Cycle detection and handling (e.g., deadlock or infinite loop prevention)
  • Time and space complexity analysis of the simulation
  • Edge cases: duplicate requests, activation of already active features, missing dependencies

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.