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Google·Software Engineer·Technical Phone Screen·Intermediate

Intermediate
Apr 2026

Summary

Google SWE coding round with a board/token puzzle that's deceptively tricky once you start thinking about blocking conditions and greedy vs. optimal ordering. Not a lot of context shared beyond the problem itself.

Questions Asked (1)

Q1

You have a 1D board of cells containing tokens, coins, and empty spaces. Each turn you move one token exactly 3 cells to the right, collecting any coin it lands on. A token can't jump over or land on another token, and can't go off the board. What's the maximum number of coins you can collect across all tokens?

Algorithms & Data Structures
Author's notes

This one sat me down for a minute.

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AI HintsAI Generated

Suggested Approach

First, clarify the problem constraints and edge cases, then model the board and token movements. Recognize that tokens move independently but may block each other, so consider dynamic programming or greedy strategies to maximize coin collection.

Pro tip: Start by asking clarifying questions about the board size, token count, and whether tokens can share cells after moves. This shows attention to detail and helps avoid incorrect assumptions.

1. Clarify the problem

Ask about board size, number of tokens, coin distribution, and movement rules. Confirm if tokens can move multiple times and if coins are removed after collection.

2. Model the board and movements

Represent the board as an array and tokens as movable elements. Note that each move is exactly 3 cells right, and tokens cannot overlap or jump over each other.

3. Identify subproblems and constraints

Break the problem into independent token paths, but consider interactions due to blocking. Determine if the problem can be solved with dynamic programming over positions.

4. Design an algorithm

Propose a DP approach where state includes token positions and collected coins, or a greedy strategy if tokens don't interfere. Discuss time and space complexity.

5. Test with examples

Walk through a small example to verify the algorithm, checking edge cases like tokens at the end of the board or multiple tokens blocking each other.

Key Points to Mention

  • Clarify movement constraints: exactly 3 cells right, no jumping over or landing on other tokens.
  • Consider dynamic programming with state representing token positions and collected coins.
  • Discuss greedy approaches and why they might fail due to token interactions.
  • Analyze time and space complexity of the proposed solution.
  • Handle edge cases: tokens at the right edge, multiple tokens in a row, coins behind tokens.
  • Mention potential optimizations like memoization or pruning.

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