Real-Time Rating Aggregator

Data Structures Algorithm System Design

Your task is to implement a rating aggregator system that processes reviews in real time. Each review has an integer rating (e.g., 1 to 5) and an associated timestamp represented as an integer. The system should provide two operations:

  1. addReview(timestamp, rating): Adds a new review to the system. You can assume that reviews are added in non-decreasing order of timestamps.

  2. queryAverage(startTime, endTime): Returns the average rating of all reviews with timestamps in the inclusive range [startTime, endTime].

You should design a data structure or system that efficiently supports these operations. Write code to simulate this functionality. Your solution should include handling cases where there are no reviews in the specified range (e.g., by returning a default value or an appropriate error message).

Focus on clarity, efficiency, and correctness in your implementation.