Amazon·Software Engineer·Online Assessment (OA)·Intermediate

Intermediate

Jun 2025Remote

Summary

Amazon OA question for a SWE role, apparently a pretty new problem that took a while to get fully documented. The problem statement was incomplete for a bit but eventually got filled in. Seems like a simulation/greedy type problem with some tricky edge cases around the skipping mechanic.

Questions Asked (1)

You and a colleague alternate dispatching goods from a series of warehouses. You always dispatch a fixed amount first, then your colleague dispatches a different fixed amount or skips his turn (up to a limited number of skips total). You score a point only when you clear the last unit from a warehouse. Given the warehouse inventories, your dispatch amount, your colleague's dispatch amount, and the total skips allowed, find the maximum number of points achievable.

Algorithms & Data Structures

Author's notes

This one took me a while to even understand what was being asked.

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AI HintsAI Generated

Suggested Approach

Model the process as a turn-based game where each warehouse's inventory is reduced by alternating fixed amounts, with the colleague having limited skips. Use dynamic programming to compute the maximum points, considering the state of each warehouse and remaining skips.

Pro tip: Clarify the rules upfront, especially whether skips can be used at any time and if multiple warehouses are processed sequentially. Then, break the problem into independent subproblems per warehouse and combine using DP.

1. Clarify rules and constraints

Ask questions to confirm the exact mechanics: turn order, skip usage, and whether warehouses are independent. Ensure you understand how points are scored.

2. Model per-warehouse outcomes

For a single warehouse, determine the sequence of dispatches and who clears it, given a certain number of skips used. Compute the points (0 or 1) for each possible skip allocation.

3. Define DP state and transition

Define DP[i][s] as the max points from first i warehouses using s skips. Transition by trying all possible skips for warehouse i and adding its points.

4. Optimize and implement

Precompute per-warehouse points for all skip counts, then fill DP table. Consider time and space complexity, and optimize if needed.

5. Test with examples

Walk through small examples to verify the DP logic and edge cases, such as when skips are exhausted or warehouses are cleared immediately.

Key Points to Mention

Dynamic programming with state (warehouse index, skips used)
Precomputing points per warehouse for each possible skip count
Handling the turn-based alternating dispatch and skip mechanics
Time and space complexity analysis (e.g., O(N * S * something))
Edge cases: zero inventory, skips exhausted, colleague skips affecting turn order
Greedy vs DP: why greedy may fail and DP is needed

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