力扣labuladong——一刷day93

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前言

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在数据流中计算平均数

一、力扣295. 数据流的中位数

class MedianFinder {
    private PriorityQueue<Integer> small;
    private PriorityQueue<Integer> large;
    public MedianFinder() {
        small = new PriorityQueue<>(
            (a,b)->{
                return b-a;
            }
        );
        large = new PriorityQueue<>();
    }
    
    public void addNum(int num) {
        if(small.size() >= large.size()){
            small.offer(num);
            large.offer(small.poll());
        }else{
            large.offer(num);
            small.offer(large.poll());
        }
    }
    
    public double findMedian() {
        if(small.size() > large.size()){
            return small.peek();
        }else if(large.size() > small.size()){
            return large.peek();
        }else{
            return (large.peek() + small.peek()) / 2.0;
        }
    }
}

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