## 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
``````

Thoughts:

1. with deque: trival
2. without deque: use ( i + 1) % as circular array

Code: with deque

``````class MovingAverage(object):

def __init__(self, size):
"""
:type size: int
"""
self.queue = collections.deque(maxlen = size)

def next(self, val):
"""
:type val: int
:rtype: float
"""

self.queue.append(val)
return float(sum(self.queue))/len(self.queue)

# Your MovingAverage object will be instantiated and called as such:
# obj = MovingAverage(size)
# param_1 = obj.next(val)
``````

Code: without deque

``````class MovingAverage(object):

def __init__(self, size):
"""
:type size: int
"""
self.w = [0] * size
self.n = 0
self.i = 0
self.size = size
self.sum = 0

def next(self, val):
"""
:type val: int
:rtype: float
"""
if self.n < self.size: self.n +=1

self.sum -= self.w[self.i]
self.sum += val
self.w[self.i] = val
self.i = (self.i + 1) % self.size

return float(sum(self.w))/self.n

# Your MovingAverage object will be instantiated and called as such:
# obj = MovingAverage(size)
# param_1 = obj.next(val)
``````