346. Moving Average from Data Stream

Practice Moving Average from Data Stream for free on NudgeCode: Easy, Sliding Window pattern. Write it in Python or JavaScript, run the tests in your browser, and ask for a hint when you are stuck.

Design a class that receives a stream of integers and reports the average of the last size values (or of all values so far, if fewer than size have arrived).

• MovingAverage(size) sets the window size.
• next(val) adds val to the stream and returns the current moving average.

Each test is a list of operations and their arguments; the expected output lists what each call returns (null for the constructor). Answers within 1e-5 are accepted.

Example

["MovingAverage","next","next","next","next"]
[[3],[1],[10],[3],[5]]
->  [null,1.0,5.5,4.66667,6.0]

Constraints

• 1 <= size <= 1000
• -10^5 <= val <= 10^5
• Up to 10^4 calls to next; aim for O(1) per call