【面试题】剑指offer 6

输入前序遍历和中序遍历结果，重建二叉树

BinTree.h

//#include<stdio.h>//#include<assert.h>//#include<iostream>//#include <stdlib.h>//using namespace std;//struct BinTreeNode{//int _value;//BinTreeNode* _left;//BinTreeNode* _right;//};//BinTreeNode* ConstructCore(int * startPreorder,int* endperorder,int * startInorder,int *endInorder)//{//int rootvalue=startPreorder[0];//BinTreeNode* root=new BinTreeNode();//root->_value=rootvalue;//root->_left=root->_right=NULL;//if(startPreorder==endperorder)//{//if(startInorder==endInorder&&*startPreorder==*startInorder)//{//return root;//}//else//return NULL;//}//int * rootInorder=startInorder;//while (rootInorder<=endInorder&&*rootInorder!=rootvalue)//{//++rootInorder;//}//int leftlength=rootInorder-startInorder;//int * leftPreOrderEnd=startPreorder+leftlength;//if(leftlength>0)//{//root->_left=ConstructCore(startPreorder+1,leftPreOrderEnd,startInorder,rootInorder-1);//}//if(leftlength<endperorder-startPreorder)//{//root->_right=ConstructCore(leftPreOrderEnd+1,endperorder,rootInorder+1,endInorder);//}//return root;//}//BinTreeNode* Construct(int * preorder,int* inorder,int length)//{//if (preorder==NULL||inorder==NULL||length<0)//return NULL;//return ConstructCore(preorder,preorder+length-1,inorder,inorder+length-1);//}////void _InorderPrint(BinTreeNode* root)//{//if (root==NULL)//{//return;//}//_InorderPrint(root->_left);//cout<<root->_value<<" ";//_InorderPrint(root->_right);////}//void InorderPrint(BinTreeNode* root)//{//_InorderPrint(root);//cout<<endl;//}//void test()//{//int  preorder[]={1,2,4,7,3,5,6,8};//int  inorder[]={4,7,2,1,5,3,8,6};//BinTreeNode* root=Construct(preorder,inorder,8);//InorderPrint(root);//}#include <iostream>using namespace std;struct BinTreeNode{int _value;BinTreeNode* _left;BinTreeNode* _right;};BinTreeNode* ConstructCore(int* startPreOrder,int* endPreOrder,int * startInOrder,int* endInOrder){int rootValue=startPreOrder[0];BinTreeNode* root=new BinTreeNode();root->_value=rootValue;root->_left=root->_right=NULL;if(startPreOrder==endPreOrder){if (startInOrder==endInOrder&&*startPreOrder==*startInOrder)return root;elsecout<<"测试用例错误"<<endl;}int* rootInorder=startInOrder;while (rootInorder<=endInOrder&&*rootInorder!=rootValue)      ++rootInorder;if(rootInorder==endInOrder&&*rootInorder!=rootValue)cout<<"测试用例错误"<<endl;int leftlength=rootInorder-startInOrder;int * leftEndPreorder=startPreOrder+leftlength;if(leftlength>0){root->_left=ConstructCore(startPreOrder+1,leftEndPreorder,startInOrder,rootInorder-1);}if(leftlength<endPreOrder-startPreOrder){root->_right=ConstructCore(leftEndPreorder+1,endPreOrder,rootInorder+1,endInOrder);}return root;}BinTreeNode* ConstuctBinTree(int* Preorder,int* Inorder,int length){if(Preorder==NULL||Inorder==NULL||length<0)return NULL;return ConstructCore(Preorder,Preorder+length-1,Inorder,Inorder+length-1);}void _inOrderBinTree(BinTreeNode* root){      if(root==NULL)  return ;  _inOrderBinTree(root->_left);  cout<<root->_value<<" ";  _inOrderBinTree(root->_right);}void InorderBinTree(BinTreeNode* root){if(root==NULL){cout<<"二叉树为空"<<endl;       return;}   _inOrderBinTree(root);cout<<endl;}void  test(){int Preorder[]={1,2,4,7,3,5,6,8};int Inorder[]={4,7,2,1,5,3,8,6};BinTreeNode* root=ConstuctBinTree(Preorder,Inorder,8);InorderBinTree(root);}void test2(){int *Preorder=NULL;int *Inorder=NULL;BinTreeNode* root=ConstuctBinTree(Preorder,Inorder,8);InorderBinTree(root);}void  test3(){int Preorder[]={8,7,6,5,4,3,2,1};int Inorder[]={1,2,3,4,5,6,7,8};BinTreeNode* root=ConstuctBinTree(Preorder,Inorder,8);InorderBinTree(root);}

test.c

#include "BinTree.h"int main(){test();test2();test3();system("pause");return 0;}