# LeetCode 359. Logger Rate Limiter

## Description

https://leetcode.com/problems/logger-rate-limiter/

Design a logger system that receives a stream of messages along with their timestamps. Each unique message should only be printed at most every 10 seconds (i.e. a message printed at timestamp `t` will prevent other identical messages from being printed until timestamp `t + 10`).

All messages will come in chronological order. Several messages may arrive at the same timestamp.

Implement the `Logger` class:

• `Logger()` Initializes the `logger` object.
• `bool shouldPrintMessage(int timestamp, string message)` Returns `true` if the `message` should be printed in the given `timestamp`, otherwise returns `false`.

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, next allowed timestamp for “foo” is 1 + 10 = 11 logger.shouldPrintMessage(2, “bar”); // return true, next allowed timestamp for “bar” is 2 + 10 = 12 logger.shouldPrintMessage(3, “foo”); // 3 < 11, return false logger.shouldPrintMessage(8, “bar”); // 8 < 12, return false logger.shouldPrintMessage(10, “foo”); // 10 < 11, return false logger.shouldPrintMessage(11, “foo”); // 11 >= 11, return true, next allowed timestamp for “foo” is 11 + 10 = 21

Constraints:

• `0 <= timestamp <= 109`
• Every `timestamp` will be passed in non-decreasing order (chronological order).
• `1 <= message.length <= 30`
• At most `104` calls will be made to `shouldPrintMessage`.

## Python Solution

Use a hashmap to track the last updated time of the message.

``````class Logger:

def __init__(self):
self.logger = {}

def shouldPrintMessage(self, timestamp: int, message: str) -> bool:

if message not in self.logger:
self.logger[message] = timestamp
return True

if timestamp - self.logger[message] < 10:
return False

self.logger[message] = timestamp

return True

# Your Logger object will be instantiated and called as such:
# obj = Logger()
# param_1 = obj.shouldPrintMessage(timestamp,message)``````
• Time Complexity: ~N
• Space Complexity: ~N