输入一棵二元查找树, 将该树转换为它的镜像

要求使用递归和循环两种方法.

二叉树节点定义:

typedef struct BSTreeNode{
int m_nValue;
struct BSTreeNode * m_pLeft;
struct BSTreeNode * m_pRight;
}BSTreeNode;

一.递归

void reverseBTree(BSTreeNode * bstree)
{
BSTreeNode * pnode;

if(bstree)
{
reverseBTree(bstree->m_pLeft);
reverseBTree(bstree->m_pRight);

pnode = bstree->m_pLeft;
bstree->m_pLeft = bstree->m_pRight;
bstree->m_pRight = pnode;
}
}

二. 循环

循环的实现中需要使用栈或者队列来遍历二叉树, 栈/队列中元素为树节点的指针

void reverseBTree_cycle(BSTreeNode * bstree)
{
Stack st;
BSTreeNode * current;
BSTreeNode * temp;

if(!bstree)
return;

initStack(&st);
push(&st, bstree);
while(!isEmpty(&st))
{
pop(&st, &current);

temp = current->m_pRight;
current->m_pRight = current->m_pLeft;
current->m_pLeft = temp;

if(current->m_pLeft)
push(&st, current->m_pLeft);
if(current->m_pRight)
push(&st, current->m_pRight);

}
}