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.

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;

这题用个hashmap存储一下函数名和时间就可以解决， 但是要注意， 不是每次接受log信息都把时间更新到hashmap里， 只有打印了才更新， 不打印的直接丢弃掉。

public class Logger {
    HashMap map;
    public Logger() {
            map = new HashMap<>();
    }
    public boolean shouldPrintMessage(int timestamp, String message) {
          Integer pretime = map.get(message);
          if(pretime == null || timestamp-pretime >= 10){
                 map.put(message, timestamp);
                 return true;
          }
          return false;
   }
}