Link: https://leetcode.cn/problems/logger-rate-limiter/

Question

difficulty: low
adj diff: 2

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.

Code

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class Logger {

    Map<String, Integer> map;

    public Logger() {
        map = new HashMap<String, Integer>();
    }

    public boolean shouldPrintMessage(int timestamp, String message) {
        if (map.containsKey(message) && timestamp < map.get(message) + 10) {
            return false;
        }
        map.put(message, timestamp);
        return true;
    }
}