LeetCode: Moving Average from Data Stream

// Given a stream of integers and a window size, calculate the moving average of all integers in the sliding window.

// For example,
// MovingAverage m = new MovingAverage(3);
// m.next(1) = 1
// m.next(10) = (1 + 10) / 2
// m.next(3) = (1 + 10 + 3) / 3
// m.next(5) = (10 + 3 + 5) / 3

/**
 * Your MovingAverage object will be instantiated and called as such:
 * MovingAverage obj = new MovingAverage(size);
 * double param_1 = obj.next(val);
 */
import java.util.*;
class MovingAverage{
double previousSum = 0.0;
    int maxSize;
    Queue<Integer> window;

    /** Initialize your data structure here. */
    public MovingAverage(int size) {
        this.maxSize = size;
        window = new LinkedList<Integer>();
    }
 
    public double next(int val) {
        if(window.size() == maxSize) {
            previousSum -= window.remove();
        }
     
        window.add(val);
        previousSum += val;

        return previousSum / window.size();
    }
}
public class MovingAverageFromDataStream {

public static void main(String[] args){
MovingAverage obj = new MovingAverage(3);
System.out.println(obj.next(1));// = 1
System.out.println(obj.next(10));// = (1 + 10) / 2
System.out.println(obj.next(3));// = (1 + 10 + 3) / 3
System.out.println(obj.next(5));// = (10 + 3 + 5) / 3
}
}