剑指offer--面试题64：数据流中的中位数

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题目描述

如何得到一个数据流中的中位数？如果从数据流中读出奇数个数值，那么中位数就是所有数值排序之后位于中间的数值。如果从数据流中读出偶数个数值，那么中位数就是所有数值排序之后中间两个数的平均值。

python实现：

# -*- coding:utf-8 -*-import heapqclass Solution:    def __init__(self):                 self.smallerHeap = []#大顶堆        heapq.heapify(self.smallerHeap)        self.biggerHeap = []#小顶堆        heapq.heapify(self.biggerHeap)             def Insert(self, num):        # write code here        if len(self.smallerHeap) == len(self.biggerHeap):            #在smallerHeap里加入元素            if len(self.biggerHeap)>0 and num > self.biggerHeap[0]:                tmpNum = heapq.heappushpop(self.biggerHeap, num)                heapq.heappush(self.smallerHeap, -tmpNum)            else:                heapq.heappush(self.smallerHeap, -num)#大顶堆，使用相反数        else:            #在biggerHeap里加入元素            if len(self.smallerHeap)>0 and num < -self.smallerHeap[0]:                tmpNum = heapq.heappushpop(self.smallerHeap, -num)                heapq.heappush(self.biggerHeap, -tmpNum)            else:                heapq.heappush(self.biggerHeap, num)                          def GetMedian(self, x):        # write code here        size = len(self.smallerHeap) + len(self.biggerHeap)        if size & 0x1 == 0:#偶数            return (-self.smallerHeap[0] + self.biggerHeap[0])/2.0        else:            return -self.smallerHeap[0]

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