堆排序

建大堆实现的是从大到小的排序

若要从小到大排序，则建小堆

//******************堆排序***************************

void_AdjustDown(int*a,size_t size,intparent)

{

                intchild =parent* 2 + 1;

                while(child <size)

                {

                                if(child + 1 <size&&a[child] < a[child + 1])

                                {

                                                ++child;

                                }

                                if(a[child]>a[parent])

                                {

                                                swap(a[child],a[parent]);

                                                parent= child;

                                                child =parent* 2 + 1;

                                }

                                else

                                                break;

                }

}

voidHeapSort(int*a,size_tn)

{

                assert(a);

                //建大堆

                for(inti = (n- 2) / 2; i >= 0; --i)

                {

                                _AdjustDown(a,n, i);

                }

                //排序

                intend =n- 1;

                while(end > 0)

                {

                                swap(a[0],a[end]);

                                _AdjustDown(a, end, 0);

                                end--;

                }

}

voidPrint(int*a,size_tsize)

{

                for(inti = 0; i <size; i++)

                {

                                cout <<a[i] <<" ";

                }

                cout << endl;

}

intmain()

{

                inta[] = { 1, 5, 67, 3, 45, 78, 12, 23, 89, 70 };

                intsize =sizeof(a) /sizeof(a[0]);

                HeapSort(a, size);

                Print(a, size);

                return0;

}