public class HeapSortFrom0 {
    /*
                                51
                     46                           20
             18              -10             82        65
         30      77     97       101     85
     */
    /**
     * 構建大頂堆
     */
public static void adjustHeap(int[] a, int i, int 
 
len) {
        int temp;
        temp = a[i];//最後一個節點的父節點
for (int j = 2 * i + 1; j <= len; j = 2 * j + 1) {// 沿關鍵字較大的孩子結點向下篩選
if (j + 1 <= len && a[j] < a[j + 1])
                ++j; // j為關鍵字中較大記錄的下標
if (temp >= a[j])
                break;
            a[i] = a[j];
            i = j;
            a[i] = temp;
        }
    }


    public static void 
 
heapSort(int[] a) {
        int i;
        for (i = ((a.length - 1) - 1) / 2; i >= 0; i--) {// 構建一個大頂堆
adjustHeap(a, i, a.length - 1);
        }

        //System.out.println(Arrays.toString(a));
        //System.exit(0);
for (i = a.length - 1; i > 0; i--) {// 將堆頂記錄和當前未經排序子序列的最後一個記錄交換
int temp = a[0];
            a[0
 
] = a[i];
            a[i] = temp;
            adjustHeap(a, 0, i - 1);// 將a中前i-1個記錄重新調整為大頂堆
}
    }

    public static void main(String[] args) {
        int a[] = {51, 46, 20, 18, -10, 82, 65, 30, 77, 97,101,85};
        heapSort(a);
        System.out.println(Arrays.toString(a));
    }
}