void Max_Heapify(int *a, int heap_size, int i)

{

   int left = (i<<1) + 1;

   int right = (i<<1) + 2;

   int largest = i;

   while(left<heap_size || right<heap_size)

   {

       if(left<heap_size && a[largest]<a[left])

       {

           largest = left;

       }

       if(right<heap_size && a[largest]<a[right])

       {

           largest = right;

       }

       if(i != largest)

       {

           int temp = a[largest];

           a[largest] = a[i];

           a[i] = temp;

           i = largest;

           left = (i<<1) + 1;

           right = (i<<1) + 2;

       }

       else

       {

           break;

       }

   }

}

void Build_Max_Heap(int *a, int heap_size)

{

    for(int i = heap_size / 2 - 1; i >= 0; i--)

    {

        Max_Heapify(a, heap_size, i);

    }

}

void HeapSort(int *a, int len)  //堆排序接口

{

    int heap_size = len;

    Build_Max_Heap(a,heap_size);

    for(int i = len - 1; i>=1; i--)

    {

        int temp = a[0];

        a[0] = a[i];

        a[i] = temp;

        heap_size--;

        Max_Heapify(a, heap_size, 0);

    }

}