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Amazon·Software Engineer·Technical Phone Screen·Intermediate

Intermediate
Jun 2026

Summary

Amazon SWE interview with a graph/BFS problem dressed up as a board game. Pretty classic but the details trip you up if you're not careful.

Questions Asked (1)

Q1

Implement a function that finds the minimum number of dice rolls required to reach the final square in a Snakes and Ladders game.

Algorithms & Data Structures
Author's notes

Looks like a simple BFS problem and it kind of is, but the board indexing gets messy fast.

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AI HintsAI Generated

Suggested Approach

Model the board as a graph where each square is a node and edges represent dice rolls (1-6) to other squares, adjusted for snakes and ladders. Use BFS to find the shortest path from square 1 to square N, as all edges have equal weight. Return the number of rolls (levels) when reaching N.

Pro tip: Clarify edge cases upfront: what if the start or end is on a snake/ladder? Also, mention that BFS is optimal because each roll costs 1, and you can optimize by precomputing the destination for each square.

1. Understand the problem and clarify assumptions

Confirm the board size, dice range (1-6), and that snakes/ladders are one-time teleports. Ask if the start and end squares can have snakes/ladders.

2. Model as a graph

Treat each square as a node. For each square, add directed edges to squares reachable by rolling 1-6, then apply any snake or ladder to get the final destination.

3. Apply BFS for shortest path

Use a queue to perform BFS from square 1. Track visited squares to avoid cycles. Each level of BFS represents one dice roll.

4. Handle edge cases and return result

If the end is unreachable, return -1. Otherwise, return the number of rolls when reaching the final square. Consider optimizations like precomputing moves.

Key Points to Mention

  • Graph representation: squares as nodes, dice rolls as edges
  • BFS guarantees shortest path in unweighted graph
  • Handling snakes and ladders as immediate teleports
  • Visited set to prevent infinite loops
  • Time complexity O(N) where N is board size
  • Space complexity O(N) for queue and visited

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