Logger, by Google

First, #StayHomeStaySafe!!! Hopefully all this craziness will be over soon.

Here is the problem: https://leetcode.com/problems/logger-rate-limiter/

359. Logger Rate Limiter

Easy

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;

Accepted

78,852

Submissions

114,151

An approach is to use a Hash Table where the key is the message and the value is the last time stamp when the message was printed. Then you can use this info to decide whether to print it again or not. Works well. Code is down below, cheers, ACC.

public class Logger
{
    Hashtable lastTimePrinted = null;
    /** Initialize your data structure here. */
    public Logger()
    {
        lastTimePrinted = new Hashtable();
    }

    /** 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. */
    public bool ShouldPrintMessage(int timestamp, string message)
    {
        if (!lastTimePrinted.ContainsKey(message) || (timestamp - (int)lastTimePrinted[message] >= 10))
        {
            if (!lastTimePrinted.ContainsKey(message)) lastTimePrinted.Add(message, timestamp);
            lastTimePrinted[message] = timestamp;
            return true;
        }
        return false;
    }
}