59-II. The maximum value of the queue (medium)

Title description:

请定义一个队列并实现函数 max_value 得到队列里的最大值，要求函数max_value、push_back 
和 pop_front 的均摊时间复杂度都是O(1)。
若队列为空，pop_front 和 max_value 需要返回 -1

示例 1：
输入: 
["MaxQueue","push_back","push_back","max_value","pop_front","max_value"]
[[],[1],[2],[],[],[]]
输出: [null,null,null,2,1,2]

示例 2：
输入: 
["MaxQueue","pop_front","max_value"]
[[],[],[]]
输出: [null,-1,-1]

Direct brute force method: call the queue in the collections module

import collections
class MaxQueue(object):
    
    def __init__(self):
        self.dqueue=collections.deque()

    def max_value(self):
        """
        :rtype: int
        """
        return max(self.dqueue) if self.dqueue else -1

    def push_back(self, value):
        """
        :type value: int
        :rtype: None
        """
        self.dqueue.append(value)

    def pop_front(self):
        """
        :rtype: int
        """
        return self.dqueue.popleft() if self.dqueue else -1