346. Moving Average from Data Stream

• Difficulty: Easy

• Topics: Design, Queue

• Similar Questions:

Problem:

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

Solutions:

class MovingAverage {
public:
    /** Initialize your data structure here. */
    MovingAverage(int size) {
        capacity = size;
    }

    double next(int val) {
        nums.push(val);
        sum += val;
        if (nums.size() > capacity) {
            sum -= nums.front(); nums.pop(); 
        }

        return (double) sum / nums.size();
    }
private:
    int sum = 0;
    queue<int> nums;
    int capacity;
};

/**
 * Your MovingAverage object will be instantiated and called as such:
 * MovingAverage* obj = new MovingAverage(size);
 * double param_1 = obj->next(val);
 */