Company: stripe_14oct
Difficulty: medium
Fraud Detection System Problem Description Stripe processes a huge number of card payments every day, and it has to spot merchants who are using the platform for fraud. For every charge, the card network (Visa, Mastercard and so on) sends back a response code that describes the outcome of the charge. Some response codes are normal outcomes, while others indicate fraud. You will build a simple model that uses these codes to decide which merchants are fraudulent. Every merchant has a Merchant Consumer Code (MCC) that describes its kind of business. Some kinds of business (for example airlines or event venues) are riskier than others, so each MCC has its own fraud threshold. There is also a minimum number of charges that a merchant must have before it can be judged at all, so that a merchant is not marked because its first one or two charges happen to be fraudulent. The charges are processed one by one, in the order given. After each charge, look at the merchant that made it: A charge is