【java】最大堆和最小堆的建立

最大堆

public class MaxHeap {
    private static int size = 0;
    private void maxHeap(int k, Integer key, Integer[] array){
        while (k > 0){
            //父节点，即array的中点
            int parent = (k - 1) >>> 1;
            Integer e= array[parent];
            if (key.compareTo(e) <= 0){
                break;
            }
            array[k] = e;
            k = parent;
        }
        array[k] = key;
        ++size;
    }

    public static void main(String[] args) {
        MaxHeap maxHeap = new MaxHeap();
        Integer[] array = new Integer[10];
        maxHeap.maxHeap(size,2,array);
        maxHeap.maxHeap(size,4,array);
        maxHeap.maxHeap(size,6,array);
        maxHeap.maxHeap(size,1,array);
        maxHeap.maxHeap(size,4,array);
        for (int i = 0; i< size; i++){
            System.out.print(array[i] + "\t");
            //output 6	4	4	1	2
        }
    }
}

最小堆

将上述代码中的

if (key.compareTo(e) <= 0){
      break;
}

改为如下，即建立最小堆

if (key.compareTo(e) >= 0){
    break;
}