码迷,mamicode.com
首页 > 其他好文 > 详细

295. Find Median from Data Stream

时间:2016-12-05 07:48:18      阅读:204      评论:0      收藏:0      [点我收藏+]

标签:code   public   eve   for   object   div   struct   priority   element   

Median is the middle value in an ordered integer list. If the size of the list is even, there is no middle value. So the median is the mean of the two middle value.

Examples: 

[2,3,4] , the median is 3

[2,3], the median is (2 + 3) / 2 = 2.5

Design a data structure that supports the following two operations:

  • void addNum(int num) - Add a integer number from the data stream to the data structure.
  • double findMedian() - Return the median of all elements so far.

For example:

add(1)
add(2)
findMedian() -> 1.5
add(3) 
findMedian() -> 2

public class MedianFinder {
    int count = 0;
    int median = 0;
    PriorityQueue<Integer> q1 = new PriorityQueue<Integer>(new Comparator<Integer>(){
        public int compare(Integer a, Integer b){
            return b-a;
        }
    });
    PriorityQueue<Integer> q2 = new PriorityQueue<Integer>();
    // Adds a number into the data structure.
    public void addNum(int num) {
        count++;
        q1.add(num);
        q2.add(q1.poll());
        if(q1.size() < q2.size())
            q1.add(q2.poll());
    }

    // Returns the median of current data stream
    public double findMedian() {
        if(count > 0 && count % 2 == 0)
            return ((double)(q1.peek()) + (double)(q2.peek()))/2.0;
        else
            return q1.peek();
    }
};

// Your MedianFinder object will be instantiated and called as such:
// MedianFinder mf = new MedianFinder();
// mf.addNum(1);
// mf.findMedian();

 

295. Find Median from Data Stream

标签:code   public   eve   for   object   div   struct   priority   element   

原文地址:http://www.cnblogs.com/joannacode/p/6132575.html

(0)
(0)
   
举报
评论 一句话评论(0
登录后才能评论!
© 2014 mamicode.com 版权所有  联系我们:gaon5@hotmail.com
迷上了代码!