642.moving-average-from-data-stream.py

#  Tag: Data Stream, Sliding Window, Queue
#  Time: O(1)
#  Space: O(K)
#  Ref: Leetcode-346
#  Note: -

#  Given a stream of integers and a window size, calculate the moving average of all integers in the sliding window.
#  
#  **Example 1:**
#  ```
#  MovingAverage m = new MovingAverage(3);
#  m.next(1) = 1 // return 1.00000
#  m.next(10) = (1 + 10) / 2 // return 5.50000
#  m.next(3) = (1 + 10 + 3) / 3 // return 4.66667
#  m.next(5) = (10 + 3 + 5) / 3 // return 6.00000
#  ```
#  
#  

from collections import deque
class MovingAverage(object):
    """
    @param: size: An integer
    """
    def __init__(self, size):
        # do intialization if necessary
        self.q = deque()
        self.size = size
        self.total = 0
    """
    @param: val: An integer
    @return:  
    """
    def next(self, val):
        # write your code here
        self.total += val
        self.q.append(val)
        if len(self.q) > self.size:
            left = self.q.popleft()
            self.total -= left

        return self.total / min(self.size, len(self.q))

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