【剑指 Offer 41. 数据流中的中位数】（ArrayList数组排序）

【解题思路】

设置一个动态数组，可以随时插入新的值。对数组进行排序后，可以计算中位数。

class MedianFinder {
    ArrayList<Integer> list;
    /** initialize your data structure here. */
    public MedianFinder() {
        list = new ArrayList<Integer>();
    }
    
    public void addNum(int num) {
       list.add(num);
    }
    
    public double findMedian() {
       Collections.sort(list);
       int len = list.size();
       if(len % 2 == 0)
       {
           return (double)(list.get(len/2 - 1) + list.get(len/2))/2;
       }
       else
       {
           return list.get(len/2);
       }
    }
}

/**
 * Your MedianFinder object will be instantiated and called as such:
 * MedianFinder obj = new MedianFinder();
 * obj.addNum(num);
 * double param_2 = obj.findMedian();
 */

 Arraylist数组排序

ArrayList<Integer> list = new ArrayList<Integer>();
Collections.sort(list);
int len = list.size();