359 Logger Rate Limiter

Design a logger system that receive stream of messages along with its timestamps, each message should be printed if and only if it is not printed in the last 10 seconds.

Given a message and a timestamp (in seconds granularity), return true if the message should be printed in the given timestamp, otherwise returns false.

It is possible that several messages arrive roughly at the same time.

Example:

Logger logger = new Logger();

// logging string "foo" at timestamp 1
logger.shouldPrintMessage(1, "foo"); returns true; 

// logging string "bar" at timestamp 2
logger.shouldPrintMessage(2,"bar"); returns true;

// logging string "foo" at timestamp 3
logger.shouldPrintMessage(3,"foo"); returns false;

// logging string "bar" at timestamp 8
logger.shouldPrintMessage(8,"bar"); returns false;

// logging string "foo" at timestamp 10
logger.shouldPrintMessage(10,"foo"); returns false;

// logging string "foo" at timestamp 11
logger.shouldPrintMessage(11,"foo"); returns true;

The Idea: Initialize a dictionary. If a message not contained with the dictionary, the message must always be accepted and stored into the dictionary. Otherwise, if the message exists, then it should only be logged if and only if the difference between the previous message time stamp and the current time stamp is greater than or equal to zero. Update the table again. Otherwise, return false.

Complexity: O(n) average time where n is the number of logs. O(m) space where m is the unique number of log messages.

class Logger(object):

    def __init__(self):
        """
        Initialize your data structure here.
        """
        self.logger = {}

    def shouldPrintMessage(self, timestamp, message):
        """
        Returns true if the message should be printed in the given timestamp, otherwise returns false.
        If this method returns false, the message will not be printed.
        The timestamp is in seconds granularity.
        :type timestamp: int
        :type message: str
        :rtype: bool
        """

        if (not self.logger.__contains__(message)):
            self.logger[message] = timestamp
            return True
        elif timestamp - self.logger[message] >= 10:
            self.logger[message] = timestamp
            return True
        else:
            return False



# Your Logger object will be instantiated and called as such:
# obj = Logger()
# param_1 = obj.shouldPrintMessage(timestamp,message)