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Google·Software Engineer·Technical Phone Screen·Intermediate

Intermediate
May 2026

Summary

Google SWE interview with a board game simulation problem. The kind of question that looks deceptively simple until you start thinking about state and move ordering, and then it gets messy fast.

Questions Asked (1)

Q1

You have a 1D board represented as a string of dots, tokens, and coins. Tokens can jump exactly 3 positions to the right, can't land on other tokens, and collect any coin they land on (not ones they jump over). What's the maximum number of coins you can collect with optimal moves?

Algorithms & Data Structures
Author's notes

I spent the first few minutes just re-reading the constraints because I kept second-guessing whether tokens block each other or just the destination cell.

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AI HintsAI Generated

Suggested Approach

Model the problem as a dynamic programming problem where the state is the position of the token and the set of collected coins. Since tokens move independently and only interact by blocking landings, consider each token separately and use DP to maximize coins collected without conflicts. Alternatively, treat it as a longest path problem in a DAG where nodes are positions and edges represent valid jumps, with weights equal to coins collected on landing.

Pro tip: Clarify the rules first: ask if tokens can jump over each other, if multiple tokens can occupy the same position, and if coins are removed after collection. This shows attention to detail and avoids incorrect assumptions.

1. Clarify the problem

Ask clarifying questions about token movement, coin collection, and interactions between tokens to ensure you understand the constraints.

2. Define the state and transitions

Identify that each token's position and the set of collected coins define the state. Transitions are jumps of exactly 3 positions to the right, landing on empty spots or coins.

3. Choose an algorithm

Use dynamic programming or graph search (e.g., BFS/DFS with memoization) to explore all valid sequences of moves and maximize coins.

4. Handle token interactions

Account for the fact that tokens cannot land on each other, so moves must be coordinated. Consider processing tokens in order or using a DP that tracks occupied positions.

5. Analyze complexity and optimize

Discuss time and space complexity, and suggest optimizations like greedy choices if applicable, or pruning in the search.

Key Points to Mention

  • Dynamic programming with state (position, collected coins) or (position, token configuration).
  • Graph representation: nodes as positions, edges as valid jumps, weights as coins.
  • Token independence vs. interaction: tokens block each other's landings.
  • Greedy approach may fail; need to consider all possibilities.
  • Time complexity: O(n * 2^k) if k tokens, or O(n^2) with careful DP.
  • Edge cases: no coins, no valid moves, tokens at the end of the board.

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