Logger Rate Limiter

Your document is well-written and follows the expected format closely. I’ve made a few minor refinements for consistency, formatting, and clarity—especially around the Examples section and code formatting.

Here's the production-ready version:

Problem Statement

A logging system receives messages along with their timestamps. Each unique message has a restriction: it can only be printed once every 10 seconds. That means if a message is printed at timestamp t, any identical message attempted before t + 10 should be rejected.

Implement the Logger class with the following methods:

• Logger(): Initializes the logging system.
• bool shouldPrintMessage(int timestamp, string message): Returns true if the message should be printed at the given timestamp; otherwise, returns false.

Timestamps are given 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");  // true: first occurrence, next allowed at 11
logger.shouldPrintMessage(2, "bar");  // true: first occurrence, next allowed at 12
logger.shouldPrintMessage(3, "foo");  // false: 3 < 11
logger.shouldPrintMessage(8, "bar");  // false: 8 < 12
logger.shouldPrintMessage(10, "foo"); // false: 10 < 11
logger.shouldPrintMessage(11, "foo"); // true: 11 >= 11, next allowed at 21

Constraints

• 0 <= timestamp <= 10⁹
• Each timestamp is non-decreasing.
• 1 <= message.length <= 30
• At most 10⁴ calls will be made to shouldPrintMessage.

Approach and Intuition

To manage log requests efficiently:

1. Use a Hash Map: Store each message along with the next valid timestamp when it can be printed again.

2. Constructor Initialization: When the Logger object is initialized, create an empty hash map.

3. Handle Logging:

   • For shouldPrintMessage(timestamp, message):

     • If the message does not exist in the map or timestamp >= map[message], update map[message] = timestamp + 10 and return true.
     • Otherwise, return false.

This approach ensures each call operates in constant time, O(1), and efficiently supports up to 10⁴ calls.

Solutions

class LogPrinter {
  private HashMap<String, Integer> messageTimestampMap;

  public LogPrinter() {
    messageTimestampMap = new HashMap<String, Integer>();
  }

  public boolean canPrint(int timestamp, String message) {

    if (!this.messageTimestampMap.containsKey(message)) {
      this.messageTimestampMap.put(message, timestamp);
      return true;
    }

    Integer lastPrinted = this.messageTimestampMap.get(message);
    if (timestamp - lastPrinted >= 10) {
      this.messageTimestampMap.put(message, timestamp);
      return true;
    } else
      return false;
  }
}