Problem

Design a rate limiter for an API that allows a maximum of max_requests requests within a time window of time_window seconds for each user. If a user exceeds the allowed requests, the API should deny the requests until the time window resets.

Input

• max_requests: an integer representing the maximum number of requests allowed in the time window.
• time_window: an integer representing the duration of the time window in seconds.
• user_id: a string representing the unique identifier for the user making the requests.
• timestamp: an integer representing the current time in seconds since the epoch.

Output

• Return True if the request is allowed, False otherwise.

Examples

Example 1:

rate_limiter(5, 10, 'user1', 1)  # Output: True
rate_limiter(5, 10, 'user1', 2)  # Output: True
rate_limiter(5, 10, 'user1', 3)  # Output: True
rate_limiter(5, 10, 'user1', 11) # Output: True
rate_limiter(5, 10, 'user1', 12) # Output: True
rate_limiter(5, 10, 'user1', 13) # Output: False

Constraints

• 1 <= max_requests <= 100
• 1 <= time_window <= 100
• 1 <= timestamp <= 10^9