346

Author: tech-cow

README.md

@@ -62,5 +62,6 @@ Success is like pregnancy, Everybody congratulates you but nobody knows how many
 |  #  | Title | Solution | Time | Space | Difficulty |Tag| Note|
 |-----|-------| -------- | ---- | ------|------------|---|-----|
 |155|[Min Stack](https://leetcode.com/problems/min-stack/#/description)| [Python](./stack_queue/minStack.py) | _O(1)_| _O(n)_  | Easy | ||
-|225|[Implement Stack using Queues](https://leetcode.com/problems/implement-stack-using-queues/#/description)| [Python](./stack_queue/queueStack.py) | push/top/pop: _O(n)_| _O(n)_  | Easy | ||
+|225|[Implement Stack using Queues](https://leetcode.com/problems/implement-stack-using-queues/#/description)| [Python](./stack_queue/queueStack.py) | push/pop: _O(1)_ top:_O(n)_ | _O(n)_  | Easy | ||
 |20|[Valid Parentheses](https://leetcode.com/problems/valid-parentheses/#/description)| [Python](./stack_queue/isValid.py) | _O(n)_| _O(n)_  | Easy | ||
+|346|[Moving Average from Data Stream](https://leetcode.com/problems/moving-average-from-data-stream/#/description)| [Python](./stack_queue/movingAverage.py) | _O(1)_| _O(n)_  | Easy | ||

stack_queue/movingAverage.py

@@ -0,0 +1,31 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+
+# Author: Yu Zhou
+
+# ****************
+# Descrption:
+# 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.
+# ****************
+
+# 思路：
+# 没什么难度，基础的stack知识，当size超过self.size的时候，pop掉第一个进入queue的，再加上新的就行了
+# 若没超过size，就继续push
+
+# ****************
+# Final Solution *
+# ****************
+class MovingAverage(object):
+    def __init__(self, size):
+        self.size = size
+        self.queue = []
+
+    def next(self, val):
+        if not self.queue or len(self.queue) < self.size:
+            self.queue.append(val)
+        else:
+            self.queue.pop(0)
+            self.queue.append(val)
+        return float(sum(self.queue)) / len(self.queue)