数据结构-重建二叉树

#include <iostream>

using namespace std;

struct BinaryTreeNode{
    int data;
    BinaryTreeNode* lchild;
    BinaryTreeNode* rchild;
};

BinaryTreeNode* Rebuilt(int *pre,int* preEnd,int* in,int* inEnd){
    BinaryTreeNode* root = new BinaryTreeNode;
    root->data = pre[0];
    root->lchild = root->rchild = NULL;

    if(pre == preEnd){    //循环结束条件
        return root;
    }

    int* curP = in;
    while(*curP != pre[0] && in < inEnd){   //寻找中序和先序相同的节点
        curP++;
    }

    int LchildSize = curP - in;
    int* LchildEnd = pre + LchildSize ;

    if(LchildSize > 0){
        root->lchild = Rebuilt(pre+1,pre+LchildSize,in,curP-1);     //控制左节点范围进行递归
    }

    if((preEnd - pre) > LchildSize){
        root->rchild = Rebuilt(pre+LchildSize+1,preEnd,curP+1,inEnd);
    }

    return root;
}

BinaryTreeNode* Start(int* pre,int* in,int size){
    if(pre == NULL || in == NULL){
        return NULL;
    }

    return Rebuilt(pre,pre+size-1,in,in+size-1);   //控制左右子节点的范围
}

void PreOrder(BinaryTreeNode* root){
    if(root != NULL){
        cout << root->data << " ";
        PreOrder(root->lchild);
        PreOrder(root->rchild);
    }
}

void InOrder(BinaryTreeNode* root){
    if(root != NULL){
        InOrder(root->lchild);
        cout << root->data << " ";
        InOrder(root->rchild);
    }
}

void PostOrder(BinaryTreeNode* root){
    if(root != NULL){
        PostOrder(root->lchild);
        PostOrder(root->rchild);
        cout << root->data << " ";
    }
}

int main()
{
    int Pre[] = {1,2,4,7,3,5,6,8};
    int In[] = {4,7,2,1,5,3,8,6};
    int Size = sizeof(Pre)/sizeof(int);   //获取长度，以便得到尾指针

    BinaryTreeNode *root = Start(Pre,In,Size);

    cout << "先序遍历： " ;
    PreOrder(root);
    cout << endl;
    cout << "中序遍历： " ;
    InOrder(root);
    cout << endl;
    cout << "后序遍历： " ;
    PostOrder(root);
    return 0;
}