Stripe计算机科学面试真题

Design a ledger system focusing on the ledger aspect rather than a payment service. Discuss your design approach and how you would satisfy the interviewer's requirements.

You work for a company that runs a payments API as a web service, and bad actors often try to defraud your service. One common fraud attack vector is when previously 'good' customer accounts are taken over by bad actors, which we call 'account takeovers'. Design a system to identify and respond to these account takeovers. Consider that bad actors might have taken over the account by guessing a weak password or using passwords found in other leaks on the web; or they might have purchased the account from an unscrupulous merchant. The bad actor then uses the account to make charges against stolen credit cards and transfer funds from the merchant’s account to their own. It’s hard to identify these occurrences because the accounts have a history of good, non-suspicious behavior. It’s possible to catch these account takeovers because they relate to a change in behavior, either in the payments that the merchant is processing or changes in details (login IP, for example) in how the account is being accessed. We need to catch these occurrences as quickly as possible when they occur because in a matter of hours or days a bad actor can steal a lot of money. Design a machine learning system to identify the account takeover issues in Stripe.

Design a system that can handle the storage of registration and login information for a warehouse system. Discuss the components and architecture you would use, how you would handle data consistency and integrity, and any scalability considerations.

Given an input string representing currency conversion rates in the format 'USD:AUD:1.4,CAD:USD:0.8,USD:JPY:110', implement a function that performs the following tasks: Part 1: Return the direct conversion rate for a given pair of currency codes if it is recorded in the input string. Part 2: If the conversion rate can be calculated through one intermediate currency (e.g., CAD to AUD via USD), return this rate as well. Part 3: When calculating the conversion rate in Part 2, use the 'best conversion calculation available'. Part 4: The function should be able to return all possible conversion rate pairs that can be calculated from the input string.