346. 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

class MovingAverage {
public:
    /** Initialize your data structure here. */
    MovingAverage(int size) : m_size(size), m_sum(0) {
        
    }
    
    double next(int val) {
        m_q.push(val);
        m_sum += val;
        if (m_q.size() > m_size) {
            m_sum -= m_q.front();
            m_q.pop();
        }
        return (double)m_sum / m_q.size();
    }
private:
    int m_size;
    int m_sum;
    queue<int> m_q;
};