java实现的堆排序小示例

Posted 2022-01-31 Neo_Gamer

写了个堆排序，结果是正确的，达到预期，请各路朋友指教。

public class HeapSortDemo 

    public static void main(String[] args) 
        int[] array = 12, 7, 20, 13, 34, 9, 18, 25, 6;
        for (int j = array.length; j > 0; j--) 
            // 调整堆
            adjustHeap(array, j);
            // 将每次调整后得到的最大的数放到后面
            swap(array, 0, j - 1);
        
        System.out.println(Arrays.toString(array));
    

    private static void adjustHeap(int[] array, int length) 
        // 非叶子节点数目
        int notLeafNodeSize = length/2;
        for (int i = notLeafNodeSize - 1; i >= 0; i --) 
            int left = 2*i + 1;
            int right = 2*i + 2;
            // 左右子节点与当前节点交换
            if (left < length && array[left] > array[i]) 
                swap(array, left, i);
            
            if (right < length && array[right] > array[i]) 
                swap(array, i, right);
            
        
    

    private static void swap(int[] array, int aIndex, int bIndex) 
        int a = array[aIndex];
        array[aIndex] = array[bIndex];
        array[bIndex] = a;