[Swift]LeetCode346. 从数据流中移动平均值 $ Moving Average from Data Stream

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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

---

给定整数流和窗口大小，计算滑动窗口中所有整数的移动平均值。

例如，

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

---

Solution:

class MovingAverage {
    var q:[Int] = [Int]()
    var size:Int = 0
    var sum:Double = 0
    init(_ size:Int)
    {
        self.size = size
        sum = 0        
    }
    
    func next(_ val:Int) -> Double
    {
        if q.count >= size
        {
            let num:Double = Double(q.removeFirst())
            sum -= num
        }
        q.append(val)
        sum += Double(val)
        return sum / Double(q.count)
    }
}

点击：Playground测试

var m:MovingAverage = MovingAverage(3)
//m.next(1) = 1
print(m.next(1))
//Print 1.0

//m.next(10) = (1 + 10) / 2
print(m.next(10))
//Print 5.5

//m.next(3) = (1 + 10 + 3) / 3
print(m.next(3))
//Print 4.666666666666667

//m.next(5) = (10 + 3 + 5) / 3
print(m.next(5))
//Print 6.0