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Brex·Software Engineer·Technical Phone Screen·Intermediate

Intermediate
Jun 2026

Summary

Brex software engineer screen with a pretty bite-sized coding problem. Nothing crazy, but the data modeling angle made it a little more interesting than your typical leetcode grind.

Questions Asked (1)

Q1

Given a card with a gem cost per color and a player's gem inventory, implement a function that returns true if the player can afford the card.

Algorithms & Data StructuresData Modeling
Author's notes

Pretty clean problem once you strip it down.

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AI HintsAI Generated

Suggested Approach

Clarify the data model for card costs and inventory, then iterate over each color to check if the player has enough gems. Handle edge cases like missing colors and ensure the solution is efficient.

Pro tip: Mention that you would use a hash map for O(1) lookups and discuss how to extend the solution if the game allows substituting gems or has wildcards.

1. Clarify the problem

Ask questions to confirm the data structures: are costs and inventory represented as maps from color to integer? Are there any special rules like wildcards?

2. Define the algorithm

Iterate through each color in the card's cost. For each color, check if the player's inventory has at least that many gems.

3. Handle edge cases

Consider cases where the card has no cost, the inventory is empty, or a color is missing from the inventory (treat as zero).

4. Analyze complexity

State that the time complexity is O(n) where n is the number of colors, and space complexity is O(1) beyond the input.

5. Discuss extensions

Mention how to adapt the solution if the game allows gem substitution or if costs are represented as a list of pairs.

Key Points to Mention

  • Use a hash map (dictionary) for O(1) lookups of gem counts.
  • Iterate over the card's cost map, not the inventory, to avoid unnecessary checks.
  • Treat missing colors in inventory as zero.
  • Time complexity is O(k) where k is the number of colors in the card's cost.
  • Space complexity is O(1) extra space.
  • Consider edge cases like empty cost or inventory.

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