中序和前序建立二叉树

//main.cpp

#include<iostream>

using namespace std;

typedef char TElemType;

typedef struct node

{

         TElemType data;

         struct node *lchild;

         struct node *rchild;

}BiTNode,*BinTree;

BiTNode *creatBinTree(TElemType *VLR,TElemType *LVR,int n)//由中序序列和前序序列构造二叉树

{

         if(n==0)

                   return NULL;

         int k=0;

         while(VLR[0]!=LVR[k])

                   k++;

         BiTNode *t=new BiTNode;

         if(t==NULL)

         {

                   cerr<<"存储分配失败！"<<endl;

                   exit(0);

         }

         t->data=VLR[0];

         t->lchild=creatBinTree(VLR+1,LVR,k);//从前序VLR+1开始对中序序列的左子序列0~k-1的k个元素递归建立左子树

         t->rchild=creatBinTree(VLR+k+1,LVR+k+1,n-k-1);//从前序VLR+1+k开始对中序序列的右子序列k+1~n-1的n-k+1个元素递归建立右子树

         return t;

}

void ClearBinTree(BinTree &T)//摧毁一棵树

{

         if(T!=NULL)

         {

                   ClearBinTree(T->lchild);

                   ClearBinTree(T->rchild);

                   delete T;T=NULL;

         }

}

void PostOrder(BiTNode *T)

{

         if(T!=NULL)

         {

                   PostOrder(T->lchild);

                   PostOrder(T->rchild);

                   cout<<T->data<<'\t';

         }

}

 

void main()

{

         TElemType *VLR=new TElemType[20];TElemType *LVR=new TElemType[20];int number;

         cout<<"请输入前序序列:"<<endl;

         cin>>VLR;

         cout<<"请输入中序序列:"<<endl;

         cin>>LVR;

         BiTNode *T=creatBinTree(VLR,LVR,strlen(VLR));

         PostOrder(T);

         cout<<endl;

}

 

 

 

 

/*

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HBDFAEKCG

*/