Leetcode 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.

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

 

思路：本题比较简单，在__init__的时候，先构造一个stack = []。然后逐个往里面push元素，如果长度达到window size了，需要先pop最上面的一个元素。

class MovingAverage(object):

    def __init__(self, size):
        """
        Initialize your data structure here.
        :type size: int
        """
        self.win_size = size
        self.stack = []
        

    def next(self, val):
        """
        :type val: int
        :rtype: float
        """
        if len(self.stack) < self.win_size:
            self.stack.append(float(val))
            return sum(self.stack)/len(self.stack)
        else:
            self.stack.pop(0)
            self.stack.append(float(val))
            return float(sum(self.stack)/len(self.stack))