Stripe Hard Interview Questions

To improve user experience, Stripe needs a data structure to represent users' transaction histories in a way that allows for efficient retrieval and management.
Problem statement: Design a transaction history structure where each transaction has an int transactionId, double amount, string date, and nested transactions. Implement methods to add a transaction and to retrieve the transaction with the highest amount.

• addTransaction(transactionId: int, amount: double, date: string): void: Add a transaction to the history.


• getMaxTransaction(): (int, double, string): Returns the ID, amount, and date of the transaction with the highest amount.

Example 1:
Input: addTransaction(1, 100.50, '2023-03-01')
Output: NoneExample 2:
Input: addTransaction(2, 200.75, '2023-03-02')
Output: NoneInput: getMaxTransaction()
Output: (2, 200.75, '2023-03-02')
Constraints:

• 1 <= transactionId <= 10^6


• 0 <= amount <= 10^6


• date follows the format 'YYYY-MM-DD'.

In order to protect our APIs from abuse and to ensure fair usage, Stripe requires a sliding window rate limiter that tracks the number of requests for each API key over a given time period.
Problem statement: You need to implement a rate limiter that allows a specified number of requests per minute (e.g., 100 requests) for each unique string apiKey. Ensure that the rate limiter has a method to track requests and should return a boolean indicating whether the request is allowed.

• trackRequest(apiKey: string): boolean: Returns true if the request is allowed, false otherwise.

Example 1:
Input: trackRequest('key1')
Output: true
Explanation: The request is allowed.Example 2:
Input: trackRequest('key1') (100 times)
Output: true (first 100 calls)
Output: false (101st call)
Constraints:

• 1 <= apiKey.length <= 100


• Rate limit can be bursty but should not exceed specified limits.


• Simulate up to 10^6 requests.