Logger Rate Limiter

Description

Company: Reddit

Problem Description

Design a logger system that receives a stream of timestamped messages. A message may be printed only if the same message has not been printed in the last 10 seconds.

Implement the Logger class:

• Logger() Initializes the logger.
• boolean shouldPrintMessage(int timestamp, string message) Returns true if the message should be printed at timestamp, and false otherwise.

If a call returns true, record that print so the same message stays blocked until 10 seconds have passed. Timestamps arrive in non-decreasing order.

Examples

Example 1:

Input: ["Logger","shouldPrintMessage","shouldPrintMessage","shouldPrintMessage","shouldPrintMessage","shouldPrintMessage","shouldPrintMessage"] [[],[1,"foo"],[2,"bar"],[3,"foo"],[8,"bar"],[10,"foo"],[11,"foo"]]

Output: [null,true,true,false,false,false,true]

Explanation:

Logger logger = new Logger();
logger.shouldPrintMessage(1, "foo");  // return true
logger.shouldPrintMessage(2, "bar");  // return true
logger.shouldPrintMessage(3, "foo");  // return false
logger.shouldPrintMessage(8, "bar");  // return false
logger.shouldPrintMessage(10, "foo"); // return false
logger.shouldPrintMessage(11, "foo"); // return true

Example 2:

Input: ["Logger","shouldPrintMessage","shouldPrintMessage","shouldPrintMessage","shouldPrintMessage"] [[],[1,"foo"],[1,"bar"],[1,"foo"],[11,"foo"]]

Output: [null,true,true,false,true]

Explanation:

Each message has its own cooldown window. Repeating "foo" at the same timestamp is blocked, but "bar" is tracked independently.

Constraints

• 0 <= timestamp <= 10^9
• 1 <= message.length <= 30
• message consists of lowercase English letters.
• timestamp values are in non-decreasing order.
• At most 10^4 calls will be made to shouldPrintMessage.

Company Notes

Follow-up: After the coding portion, interviewers may keep pushing on production concerns, such as how to handle high throughput, how to adapt the design for highly concurrent environments, and how you would test and deploy it.