Here we have an event log file produced by a Friends service, e.g.: Given a list of all users and the logs above, implement a function that returns the earliest timestamp at which every user became reachable from every other user via friendship connections (i.e., when the social graph first became fully connected).If the graph…

Design and implement a tiny Spreadsheet engine. Rules / constraints Follow-ups Example This mirrors the interview: start with simple DFS, then show scalability via caching + dependency invalidation, and optionally cycle detection. The VOprep team has long accompanied candidates through various major company OAs and VOs, including OpenAI, Google, Amazon, Citadel, SIG, providing real-time voice assistance, remote…

Implement Spreadsheet with Cells You are asked to design a simple Spreadsheet system consisting of multiple cells, where each cell can either contain a numeric value or depend on other cells by referencing them as children. Each cell can be represented as an object: If a cell contains a value, it’s a constant.If it contains…

Credits You’re building a system to track balances for the OpenAI API credit purchasing system. API users can purchase credit grants, specified by an ID, that are active at a timestamp and that let them use the API. Unused credit grant balances expire at a certain time. However, there’s a kink in our system: requests…

Given N free bytes in memory, implement the following two functions: Restrictions: Example (in Python): Example usage and expected behavior: Summary Core idea: manage free memory as a list of intervals. Approach: This problem mainly tests interval manipulation, state consistency, and low-level resource management logic. The VOprep team has long accompanied candidates through various major company OAs…

A comma-separated expression inside curly braces expands to a list of words.If there is a prefix before the { or a suffix after the }, they also appear in each expansion. Examples: Write a brace_expand function that takes a single pattern string and returns a list of expanded strings.If the pattern is not expandable, return…

Sending Subscription Notifications — Part 1 At Stripe, we frequently send notifications to users related to their subscriptions.Each user has an account creation date and a subscription plan with a specific duration.You’ll need to generate email subject lines corresponding to each user for different stages of their subscription, sorted by time. Your notification system will…

Part 1: Register Receivables Part 2: Contracts and Updates The VOprep team has long accompanied candidates through various major company OAs and VOs, including Stripe, Google, Amazon, Citadel, SIG, providing real-time voice assistance, remote practice, and interview pacing reminders to help you stay smooth during critical moments. If you are preparing for Stripe or similar…

Friendly reminder: If you haven’t read the previous article “Shipping Cost Calculation,” it is recommended to read it first, as this question is actually a continuation of the logic from that article. Link to the previous article 🧾 Problem Description Modify your program such that it can find shipping routes through at most one intermediate…

Part 1 — Authorization Requests Stripe accepts payments on behalf of merchants. These payments begin as Authorization Requests, which represent an intent to transfer funds from an end user’s credit card to a merchant. Our system receives these requests and decides the Outcome of each Authorization Request. For now, the system’s policy is to APPROVE…