编程之美3.9---重建二叉树&&判断结果是否能够重建

#include<iostream>using namespace std;struct Node{Node* pLeft;Node* pRight;int nValue;};bool isValid(int * pPreOrder,int *pInOrder,int nTreeLen){if(nTreeLen==0){return true;}if(pPreOrder==NULL||pInOrder==NULL){return true;}else{int LeftLen=0;int RightLen=0;int i=0;for(;i<nTreeLen;i++){if(pInOrder[i]==pPreOrder[0])break;}if(i==nTreeLen){return false;}else{LeftLen=i;RightLen=nTreeLen-i-1;bool ls=isValid(pPreOrder+1,pInOrder,LeftLen);bool rs=isValid(pPreOrder+1+LeftLen,pInOrder+1+LeftLen,RightLen);return ls&&rs;}}}void Rebuild(int * pPreOrder,int *pInOrder,int nTreeLen,Node ** pRoot){if(nTreeLen==0){return;}if(pPreOrder==NULL||pInOrder==NULL){return;}else{Node* temp=(Node *)malloc(sizeof(Node));temp->nValue=pPreOrder[0];temp->pLeft=NULL;temp->pRight=NULL;*pRoot=temp;int LeftLen=0;int RightLen=0;int i=0;for(;i<nTreeLen;i++){if(pInOrder[i]==temp->nValue)break;}LeftLen=i;RightLen=nTreeLen-i-1;Rebuild(pPreOrder+1,pInOrder,LeftLen,&(temp->pLeft));Rebuild(pPreOrder+1+LeftLen,pInOrder+1+LeftLen,RightLen,&(temp->pRight));}}void ProPrint(Node* root){if(root==NULL)return;cout<<root->nValue<<endl;ProPrint(root->pLeft);ProPrint(root->pRight);}void MidPrint(Node* root){if(root==NULL)return;MidPrint(root->pLeft);cout<<root->nValue<<endl;MidPrint(root->pRight);}int main(){int a[6]={1,2,4,3,5,6};int b[6]={4,2,1,5,3,6};if(isValid(a,b,6)){Node * prt;Rebuild(a,b,6,&prt);cout<<"前序遍历："<<endl;ProPrint(prt);cout<<"中序遍历："<<endl;MidPrint(prt);}elsecout<<"Not Valid!"<<endl;int a0[6]={1,2,4,3,5,6};int b0[6]={7,2,1,5,3,6};if(isValid(a0,b0,6)){Node * prt;Rebuild(a0,b0,6,&prt);cout<<"前序遍历："<<endl;ProPrint(prt);cout<<"中序遍历："<<endl;MidPrint(prt);}elsecout<<"Not Valid!"<<endl;int a1[1]={1};int b1[1]={1};if(isValid(a1,b1,1)){Node * prt;Rebuild(a1,b1,1,&prt);cout<<"前序遍历："<<endl;ProPrint(prt);cout<<"中序遍历："<<endl;MidPrint(prt);}elsecout<<"Not Valid!"<<endl;int a2[6]={1,2,4,3,5,6};int b2[6]={3,2,1,5,6,4};if(isValid(a2,b2,6)){Node * prt;Rebuild(a2,b2,6,&prt);cout<<"前序遍历："<<endl;ProPrint(prt);cout<<"中序遍历："<<endl;MidPrint(prt);}elsecout<<"Not Valid!"<<endl;return 0;}