题目
Given a stream of integers and a window size, calculate the moving average of all integers in the sliding window.
解题思路
维护一个deque，当数字超过size之后，每次弹出最左边的数，求和减去这个数，加上新的数
代码
class MovingAverage:
def __init__(self, size: int):
"""
Initialize your data structure here.
"""
self.size = size
self.q = deque()
self.count = 0
self.sum = 0
def next(self, val: int) -> float:
self.count += 1
self.q.append(val)
tail = self.q.popleft() if self.count > self.size else 0
self.sum = self.sum - tail + val
return self.sum / min(self.size, self.count)
