Number of Recent Calls

Key Ideas
The key idea to solve this problem is to use a sliding window approach to keep track of the number of recent calls within a specific time frame.
Problem Number
Problem Summary
Problem Summary: Given a data stream of integers and a function that returns the number of recent calls made within a certain time frame, implement the RecentCounter class to track the number of recent calls. The RecentCounter class should have a ping method that returns the number of calls made within the last 3000 milliseconds. Key Pitfalls: One key pitfall to watch out for is ensuring that the ping method efficiently handles the time frame constraint. Another potential pitfall is handling edge cases when the data stream is empty or when the ping method is called before any calls have been made.
Solution Summary
The best solution to solve this problem is to use a queue data structure. By maintaining a queue of fixed size, we can keep track of the most recent calls efficiently. Whenever a new call comes in, we add it to the queue and remove any calls that are older than 3000 milliseconds. To get the number of recent calls, we simply return the size of the queue. This solution ensures that only the relevant calls are considered and provides a constant time complexity for both adding and removing calls from the queue.
Data Stream