递归和循环两种方法完成树的镜像转换

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/*
copyright@nciaebupt 转载出处：http://blog.csdn.net/nciaebupt/article/details/8506038
题目：输入一颗二元查找树，将该树转换为它的镜像，即在转换后的二元查找树中，左子树的结点都大于右子树的结点。用递归和循环两种方法完成树的镜像转换。
例如：
8 8
/ \ 转换 / \
6 10 --> 10 6
/ \ / \ / \ / \
5 7 9 11 11 9 7 5
*/
#include <cstdlib>
#include <iostream>
#include <stack>
struct BSTreeNode
{
int value;
int flag;
BSTreeNode * left;
BSTreeNode * right;
};
//创建二叉查找树
BSTreeNode * InsertBSTree(BSTreeNode * pRoot,int value)
{
//创建节点并初始化
BSTreeNode * pNode = new BSTreeNode();
pNode->value = value;
pNode->flag = 0;
pNode->left = NULL;
pNode->right = NULL;
BSTreeNode * pCur = pRoot;
BSTreeNode * pParent = NULL;
if(pRoot == NULL)
{
pRoot = pNode;
}
else
{
while(pCur != NULL)
{
pParent = pCur;
if(value < pCur->value)
pCur = pCur->left;
else
pCur = pCur->right;
}
if(value < pParent->value)
pParent->left = pNode;
else
pParent->right = pNode;
}
return pRoot;
}
//中序遍历二叉树
void InOrderBSTree1(BSTreeNode * pRoot)
{
BSTreeNode * pCur = pRoot;
if(pCur != NULL)
{
InOrderBSTree1(pCur->left);
std::cout<<pCur->value<<std::endl;
InOrderBSTree1(pCur->right);
}
}
void InOrderBSTree(BSTreeNode * pRoot)
{
BSTreeNode cur = *pRoot;
std::stack<BSTreeNode> stack;
stack.push(cur);
while(!stack.empty())
{
if(stack.top().flag == 0)
{
stack.top().flag = 1;
if(stack.top().left != NULL)
{
stack.push(*(stack.top().left));
}
}
else
{
std::cout<<stack.top().value<<std::endl;
BSTreeNode tmp = stack.top();
stack.pop();
if(tmp.right != NULL)
{
stack.push(*(tmp.right));
}
}
}
}
//将二叉查找树转换为它的镜像，递归实现
void BSTree2MirrorRcur(BSTreeNode * pRoot)
{
if(pRoot == NULL)
{
return;
}
//交换指针
BSTreeNode * tmp = pRoot->left;
pRoot->left = pRoot->right;
pRoot->right = tmp;
//递归左子树
if(pRoot->left != NULL)
{
BSTree2MirrorRcur(pRoot->left);
}
//递归右子树
if(pRoot->right != NULL)
{
BSTree2MirrorRcur(pRoot->right);
}
}
//将二叉查找树转换为它的镜像，循环实现
void BSTree2Mirror(BSTreeNode * pRoot)
{
if(pRoot == NULL)
return;
std::stack<BSTreeNode*> pStack;
BSTreeNode * pCur = pRoot;
BSTreeNode * pTmp = NULL;
pStack.push(pCur);
while(!pStack.empty())
{
pCur = pStack.top();
pStack.pop();
pTmp = pCur->left;
pCur->left = pCur->right;
pCur->right = pTmp;
if(pCur->left != NULL)
pStack.push(pCur->left);
if(pCur->right != NULL)
pStack.push(pCur->right);
}
}
int main(int args,char **argv)
{
int array[] = {8,6,10,5,7,9,11};
int len = sizeof(array)/sizeof(int);
//创建二叉查找树
BSTreeNode * pRoot = NULL;
for(int i = 0;i < len;++i)
{
pRoot = InsertBSTree(pRoot,array[i]);
}
//中序遍历二叉树
InOrderBSTree(pRoot);
//将二叉查找树转换为它的镜像，递归实现
//BSTree2MirrorRcur(pRoot);
//中序遍历二叉树
//InOrderBSTree(pRoot);
//将二叉查找树转换为它的镜像，循环实现
BSTree2Mirror(pRoot);
//中序遍历二叉树
InOrderBSTree(pRoot);
system("pause");
return 0;
}