复习二叉搜索树作的几道题
// FindTree2.cpp : 定义控制台应用程序的入口点。
//
#include "stdafx.h"
#include <iostream>
#include "stdafx.h"
using namespace std;
typedef struct _TreeNode
{
char data;
_TreeNode* lChild;
_TreeNode* rChild;
}TreeNode,*PTreeNode;
void PreWalk(TreeNode* p)
{
if(p == NULL) return;
cout<< p->data <<endl;
if(p->lChild != NULL)
cout<< "left of "<<p->data<<endl;
PreWalk( p->lChild);
if( p->rChild != NULL)
cout<< "righ of " <<p->data<<endl;
PreWalk(p->rChild);
}
void InWalk(TreeNode* p)
{
if(p == NULL) return;
if(p->lChild != NULL)
cout<< "left of "<<p->data<<endl;
InWalk( p->lChild);
cout<<p->data<<endl;
if( p->rChild != NULL)
cout<< "righ of " <<p->data<<endl;
InWalk(p->rChild);
}
void PostWalk(TreeNode* p)
{
if(p == NULL) return;
if(p->lChild != NULL)
cout<< "left of "<<p->data<<endl;
PostWalk( p->lChild);
if( p->rChild != NULL)
cout<< "righ of " <<p->data<<endl;
PostWalk(p->rChild);
cout<<p->data<<endl;
}
void InsertFindTree2(char data,TreeNode** pTree)
{
if( *pTree == NULL )
{
TreeNode* pNode = new TreeNode;
pNode->data = data;
*pTree = pNode;
pNode->lChild = pNode->rChild= NULL;
}
else if( data < (*pTree)->data )
{
InsertFindTree2(data,&(*pTree)->lChild);
}
else
{
InsertFindTree2(data,&(*pTree)->rChild);
}
}
void CreateFindTree2( TreeNode** pTree)
{
while(true)
{
char c;
cout<<"Value:\n"<<endl;
cin>>c;
if( c == '$' )
{
break ;//结束
}
else
{
InsertFindTree2( c,pTree);
}
}
}
//
TreeNode* FindTreeNode2( char data,TreeNode** pTree)
{
TreeNode* pRetNode = NULL;
if( data == (*pTree)->data )
{
pRetNode = *pTree;
}
else if( data < (*pTree)->data )
{
pRetNode = FindTreeNode2(data,&(*pTree)->lChild);
}
else
{
pRetNode = FindTreeNode2(data,&(*pTree)->rChild);
}
return pRetNode;
}
//寻找前驱结点
TreeNode* FindPreTreeNode2( TreeNode* pNode)
{
TreeNode* pRetNode = NULL;
if( pNode->lChild == NULL )
{
return NULL;
}
else if( pNode->lChild->rChild == NULL)
{
pRetNode = pNode->lChild;
}
else
{
pRetNode = FindPreTreeNode2( pNode->lChild->rChild );
}
return pRetNode;
}
//寻找后继结点
TreeNode* FindPostTreeNode2( TreeNode* pNode)
{
TreeNode* pRetNode = NULL;
if( pNode->rChild == NULL )
{
return NULL;
}
else if( pNode->rChild->lChild == NULL)
{
pRetNode = pNode->rChild;
}
else
{
pRetNode = FindPostTreeNode2( pNode->rChild->lChild );
}
return pRetNode;
}
bool DeleteFindTree2(char data ,TreeNode* parentNode, TreeNode** pTree)
{
bool bDelete = false;
if( *pTree == NULL)
return false;
if( data == (*pTree)->data )
{
TreeNode* delNode = *pTree;
if( parentNode == NULL)
{
if( ((*pTree)->lChild != NULL) && ((*pTree)->rChild == NULL ))
{
*pTree = (*pTree)->lChild;
}
else if( ((*pTree)->rChild != NULL) && ((*pTree)->lChild == NULL ))
{
*pTree = (*pTree)->rChild;
}
else if( ((*pTree)->lChild != NULL) && ((*pTree)->rChild != NULL ))
{
//找*pTree的后继节点(可能是一个叶节点，也可能是没一个没有左孩子的节点)
TreeNode *pPostNode = (*pTree)->rChild,*pParentOfPost = NULL;
while( pPostNode != NULL)
{
if( pPostNode->lChild == NULL)
break;
pParentOfPost = pPostNode;
pPostNode = pPostNode->rChild ;
}
//先把左孩子挂到后继左孩子
pPostNode->lChild = (*pTree)->lChild;
//如果后继不是右孩子
if( pPostNode != (*pTree)->rChild )
{
//把后继右孩子挂到后继的父节点上(后继一定没有左孩子，其必为父节点的左孩子)
pParentOfPost->lChild = pPostNode->rChild;
}
*pTree = pPostNode;
}
else
{
*pTree = NULL;
}
delete delNode;
}
else
{
if( parentNode->lChild == *pTree )
{
if( ((*pTree)->lChild != NULL) && ((*pTree)->rChild == NULL ))
{
parentNode->lChild = (*pTree)->lChild;
}
else if( ((*pTree)->rChild != NULL) && ((*pTree)->lChild == NULL ))
{
parentNode->lChild = (*pTree)->rChild;
}
else if( ((*pTree)->lChild != NULL) && ((*pTree)->rChild != NULL ))
{
//找*pTree的后继节点(可能是一个叶节点，也可能是没一个没有左孩子的节点)
TreeNode *pPostNode = (*pTree)->rChild,*pParentOfPost = NULL;
while( pPostNode != NULL)
{
if( pPostNode->lChild == NULL)
break;
pParentOfPost = pPostNode;
pPostNode = pPostNode->rChild ;
}
//先把左孩子挂到后继左孩子
pPostNode->lChild = (*pTree)->lChild;
//如果后继不是右孩子
if( pPostNode != (*pTree)->rChild )
{
//把后继右孩子挂到后继的父节点上(后继一定没有左孩子，其必为父节点的左孩子)
pParentOfPost->lChild = pPostNode->rChild;
}
parentNode->lChild = pPostNode;
}
else
{
parentNode->lChild = NULL;
}
delete delNode;
}
else if( parentNode->rChild == *pTree )
{
if( ((*pTree)->lChild != NULL) && ((*pTree)->rChild == NULL ))
{
parentNode->rChild = (*pTree)->lChild;
}
else if( ((*pTree)->rChild != NULL) && ((*pTree)->lChild == NULL ))
{
parentNode->rChild = (*pTree)->rChild;
}
else if( ((*pTree)->lChild != NULL) && ((*pTree)->rChild != NULL ))
{
//找*pTree的后继节点(可能是一个叶节点，也可能是没一个没有左孩子的节点)
TreeNode *pPostNode = (*pTree)->rChild,*pParentOfPost = NULL;
while( pPostNode != NULL)
{
if( pPostNode->lChild == NULL)
break;
pParentOfPost = pPostNode;
pPostNode = pPostNode->rChild ;
}
//先把左孩子挂到后继左孩子
pPostNode->lChild = (*pTree)->lChild;
//如果后继不是右孩子
if( pPostNode != (*pTree)->rChild )
{
//把后继右孩子挂到后继的父节点上(后继一定没有左孩子，其必为父节点的左孩子)
pParentOfPost->lChild = pPostNode->rChild;
}
parentNode->rChild = pPostNode;
}
else
{
parentNode->rChild = NULL;
}
delete delNode;
}
}
bDelete = true;
}
else if( data < (*pTree)->data )
{
bDelete = DeleteFindTree2(data,*pTree,&(*pTree)->lChild);
}
else
{
bDelete = DeleteFindTree2(data,*pTree,&(*pTree)->rChild);
}
return bDelete;
}
int _tmain(int argc, _TCHAR* argv[])
{
TreeNode* _root = NULL;
CreateFindTree2(&_root);
PreWalk( _root );
if( DeleteFindTree2('3',NULL,&_root))
{
cout<<" delete ok!\n"<<endl;
}
else
{
cout<<" can not find this node !\n"<<endl;
}
PreWalk( _root);
return 0;
}
