← Stripe Interview Insights

Stripe·Software Engineer·Technical Phone Screen·Intermediate

Intermediate
Jun 2026

Summary

Stripe SWE coding round, pretty straightforward problem about picking minimum cost options across a set of factories. Nothing too wild but it felt like a warmup question that might go somewhere more complex.

Questions Asked (1)

Q1

Given N factories, each with a list of cost options, pick exactly one option per factory to minimize the total cost. Return that minimum total cost.

Algorithms & Data Structures
Author's notes

Pretty much just grab the minimum from each factory's list and sum them up.

Create a free account to read the full note

AI HintsAI Generated

Suggested Approach

Clarify that the problem reduces to summing the minimum cost from each factory's list, since choices are independent. Then discuss edge cases and implementation details, such as handling empty lists or negative costs.

Pro tip: Mention that if the problem had constraints linking factories (e.g., total budget), it would become a knapsack-like problem, but here independence allows a greedy solution. This shows you understand problem structure and can adapt.

1. Understand the problem

Restate the problem: N factories, each with a list of costs, choose exactly one per factory to minimize total cost. Confirm that choices are independent.

2. Identify the optimal substructure

Since each factory's choice doesn't affect others, the optimal total is the sum of the minimum cost from each factory's list.

3. Handle edge cases

Consider empty lists (invalid input), negative costs (still pick minimum), and large N (efficiency).

4. Implement and analyze

Iterate through each factory, find the minimum cost, and accumulate. Time complexity O(total number of options), space O(1).

Key Points to Mention

  • Independence of choices across factories
  • Greedy approach: pick local minimum for each factory
  • Time complexity: O(sum of list lengths)
  • Space complexity: O(1) extra space
  • Edge cases: empty lists, negative costs, single factory
  • Alternative: if constraints linked factories, dynamic programming might be needed

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