堆排序

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建初始堆方法一：

（1）从最大下标的非叶子节点开始，比较其值和左右孩子的值，进行调整，同时对调整节点的子树递归地进行类似的做法；// 调整index节点及其子树，使其满足大根堆性质，void HeapAdjust(int *a,int index,int heap_size){int left = 2*index;int right = 2*index + 1;int dest = index,temp;if (left <= heap_size && a[left]> a[dest]){dest = left;}if (right <= heap_size && a[right]> a[dest]){dest = right;}if (dest != index){temp = a[index];a[index] = a[dest];a[dest] = temp;HeapAdjust(a,dest,heap_size);}}void buildHeap(int *a,int heap_size)  //下标从heap_size/2+1 到 heap_size的节点，在二叉树中为叶子节点，可以看成只有一个节点的堆，满足最大堆。所以建堆从下标heap_size/2开始，逐渐减至1.{for (int i = heap_size/2;i >= 1;i--){HeapAdjust(a,i,heap_size);}}

堆排序：

void myHeapSort(int *a,int heap_size){buildHeap(a,10);  //建初始堆for (int i = heap_size; i >= 2; i--){int temp = a[i];a[i] = a[1];a[1] = temp;  // 将当前堆最大值和数组尾部值交换，交换后最大值加入到有序数组HeapAdjust(a,1,i-1); // 交换后的堆顶元素不满足堆的性质，注意此时只有堆顶元素不满足大根堆的性质，只需调整a[1]即可。}}

建初始堆方法二：插入法建堆

void insertToHeap(int *a,int i,int key){while ((i/2 >=1) && a[i] > a[i/2])  //新加入的节点比父节点大，与父节点交换，同时一直向上与父节点交换直至下标为1{int temp = a[i];a[i] = a[i/2];a[i/2] =temp;i/=2;}} void buildHeapForInsert(int *a, int length) //插入法建堆，初始堆为a[1],然后逐一将a[i]（i=2,……length）添加到堆中。每添加一个，保证形成的堆均为最大堆{int heap_size = 1;for (int i = 2;i<= length;i++){heap_size++;insertToHeap(a,heap_size,a[i]);}}void myHeapSortForInsert(int *a,int heap_size){buildHeapForInsert(a,10);  //插入法建堆for (int i = heap_size; i >= 2; i--){int temp = a[i];a[i] = a[1];a[1] = temp;HeapAdjust(a,1,i-1);}}int main(){int a[11]={0,3,9,6,12,5,8,21,16,1,10}; //堆数据从a[1]开始。a[0]为无效数据。myHeapSort(a,10);for (int i = 1;i <= 10; i++){cout<<a[i]<<" ";}cout<<endl;myHeapSortForInsert(a,10);for (int i = 1;i <= 10; i++){cout<<a[i]<<" ";}cout<<endl;system("pause");}

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