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.

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

Java Solution:

class MovingAverage {

    /** Initialize your data structure here. */

    private Queue<Integer> q;

    private double sum;

    private int maxSize;

    public MovingAverage(Integer size) {

        q = new LinkedList<Integer>();

        maxSize = size;

        sum = 0;

    }

    

    public double next(int val) {

        if(q.size() != maxSize){

            q.offer(val);

            sum+=val;

            return sum / q.size();

        }else{

            sum-=q.peek(); // subtracting from sum before removing the first element

            q.poll();

            q.offer(val);

            sum+=val;

            return sum / q.size();

        }

    }

}

/**

 * Your MovingAverage object will be instantiated and called as such:

 * MovingAverage obj = new MovingAverage(size);

 * double param_1 = obj.next(val);

 */