线索二叉树的代码实现

线索二叉树的关键点及其难点在于线索树的建立，可以先建立树，然后根据中序遍历（也可以是其他遍历）建立线索树，也可以在插入节点时建立线索二叉树。后者时间复杂度较小，但是需要注意的地方比较多。具体见代码。

 ThreadNode.h文件

template<typename Type> class ThreadTree;template<typename Type> class ThreadInorderIterator;template<typename Type> class ThreadNode{public:friend class ThreadTree<Type>;friend class ThreadInorderIterator<Type>;//每一个新建的节点的左右指针都指向自己ThreadNode():m_nleftthread(1),m_nrightthread(1){m_pleft=this;m_pright=this;}//带参的构造函数指针都指向NULLThreadNode(const Type item):m_data(item),m_pleft(NULL),m_pright(NULL),m_nleftthread(0),m_nrightthread(0){}private:int m_nleftthread,m_nrightthread;ThreadNode<Type> *m_pleft,*m_pright;Type m_data;};

ThreadTree.h文件

#include "ThreadNode.h"template<typename Type> class ThreadInorderIterator;template<typename Type> class ThreadTree{public:friend class ThreadInorderIterator<Type>;//构造的根节点的左右指针都指向自己ThreadTree():m_proot(new ThreadNode<Type>()){}private:ThreadNode<Type> *m_proot;};

ThreadInorderIterator.h文件

#include "ThreadTree.h"template<typename Type> class ThreadInorderIterator{public:ThreadInorderIterator(ThreadTree<Type> &tree):m_ptree(tree),m_pcurrent(tree.m_proot){//InThread(m_ptree.m_proot->m_pleft,m_ptree.m_proot);}ThreadNode<Type> *First();ThreadNode<Type> *Prior();ThreadNode<Type> *Next();void Print();void Print(ThreadNode<Type> *start, int n=0);void InOrder();void Insert(ThreadNode<Type> *Node);ThreadNode<Type> *GetParent(ThreadNode<Type> *current);private:ThreadTree<Type> &m_ptree;ThreadNode<Type> *m_pcurrent;void InThread(ThreadNode<Type> *current,ThreadNode<Type> *pre);};//建立中序遍历索引template<typename Type> void ThreadInorderIterator<Type>::InThread(ThreadNode<Type> *current, ThreadNode<Type> *pre){if(current!=m_ptree.m_proot){InThread(current->m_pleft,pre);if(current->m_pleft==NULL){current->m_pleft=pre;current->m_nleftthread=1;}if(pre->m_pright==NULL){pre->m_pright=current;pre->m_nrightthread=1;}pre=current;InThread(current->m_pright,pre);}}//找到第一个被遍历的节点template<typename Type> ThreadNode<Type>* ThreadInorderIterator<Type>::First(){while(m_pcurrent->m_nleftthread==0){m_pcurrent=m_pcurrent->m_pleft;}return m_pcurrent;}template<typename Type> ThreadNode<Type>* ThreadInorderIterator<Type>::Prior(){ThreadNode<Type> *pmove=m_pcurrent->m_pleft;if(0==m_pcurrent->m_nleftthread){while(0==pmove->m_nrightthread){pmove=pmove->m_pright;}}m_pcurrent=pmove;if(m_pcurrent==m_ptree.m_proot){return NULL;}return m_pcurrent;}template<typename Type> ThreadNode<Type>* ThreadInorderIterator<Type>::Next(){ThreadNode<Type>*temp=m_pcurrent->m_pright;if(m_pcurrent->m_nrightthread==0){while(temp->m_nleftthread==0){temp=temp->m_pleft;}}if(m_pcurrent->m_pright==m_ptree.m_proot)return NULL;m_pcurrent=temp;return m_pcurrent;}template<typename Type> void ThreadInorderIterator<Type>::InOrder(){ThreadNode<Type> *pmove=m_ptree.m_proot;while(pmove->m_pleft!=m_ptree.m_proot){pmove=pmove->m_pleft;}m_pcurrent=pmove;cout<<"root";while(pmove!=m_ptree.m_proot&&pmove){cout<<"--->"<<pmove->m_data;pmove=this->Next();}cout<<"--->end";}template<typename Type> void ThreadInorderIterator<Type>::Insert(ThreadNode<Type> *Node){if(m_ptree.m_proot->m_pleft==m_ptree.m_proot){m_ptree.m_proot->m_pleft=Node;Node->m_nleftthread=Node->m_nrightthread=1;Node->m_pleft=Node->m_pright=m_ptree.m_proot;m_ptree.m_proot->m_nleftthread=0;return ;}ThreadNode<Type>*temp=m_ptree.m_proot->m_pleft;while(1){if(temp->m_data>Node->m_data){if(temp->m_nleftthread==1){Node->m_nleftthread=Node->m_nrightthread=1;temp->m_nleftthread=0;Node->m_pleft=temp->m_pleft;temp->m_pleft=Node;Node->m_pright=temp;return ;}temp=temp->m_pleft;}else if(temp->m_data<Node->m_data){if(temp->m_nrightthread==1){Node->m_nleftthread=Node->m_nrightthread=1;Node->m_pright=temp->m_pright;Node->m_nrightthread=1;temp->m_nrightthread=0;temp->m_pright=Node;Node->m_pleft=temp;temp->m_nleftthread=1;return ;}temp=temp->m_pright;}else {cout<<"this node have exit!"<<endl;return ;}}}template<typename Type> ThreadNode<Type>* ThreadInorderIterator<Type>::GetParent(ThreadNode<Type> *current){ThreadNode<Type> *pmove=current;while(0==pmove->m_nleftthread){pmove=pmove->m_pleft;}pmove=pmove->m_pleft;if(pmove==m_ptree.m_proot){if(pmove->m_pleft==current){return NULL;}}if(pmove->m_pright==current){return pmove;}pmove=pmove->m_pright;while(pmove->m_pleft!=current){pmove=pmove->m_pleft;}return pmove;}template<typename Type> void ThreadInorderIterator<Type>::Print(ThreadNode<Type> *start, int n){if(start->m_nleftthread&&start->m_nrightthread){for(int i=0;i<n;i++){cout<<"     ";}if(n>=0){cout<<start->m_data<<"--->"<<endl;}return;}if(start->m_nrightthread==0){Print(start->m_pright,n+1);}for(int i=0;i<n;i++){cout<<"     ";}if(n>=0){cout<<start->m_data<<"--->"<<endl;}if(start->m_nleftthread==0){Print(start->m_pleft,n+1);}}template<typename Type> void ThreadInorderIterator<Type>::Print(){this->InOrder();}

test.cpp文件

#include <iostream>using namespace std;#include "ThreadInorderIterator.h"int main(){ThreadTree<int> tree;ThreadInorderIterator<int> threadtree(tree);int init[10]={3,6,0,2,8,4,9,1,5,7};for(int i=0;i<10;i++){threadtree.Insert(new ThreadNode<int>(init[i]));cout<<i<<endl;}threadtree.InOrder();return 0;}