重建二叉树

题目描述

输入某二叉树的前序遍历和中序遍历的结果，请重建出该二叉树。假设输入的前序遍历和中序遍历的结果中都不含重复的数字。例如输入前序遍历序列{1,2,4,7,3,5,6,8}和中序遍历序列{4,7,2,1,5,3,8,6}，则重建二叉树并返回。

代码：

    struct TreeNode* reConstructBinaryTree(vector<int> pre,vector<int> in) {        int prelen = pre.size();        int inlen = in.size();        int i = 0;        if(prelen == 0 || inlen == 0 || inlen != prelen)            return NULL;        TreeNode* Root = new TreeNode(pre[0]);        for(i = 0;i < inlen;i++){            if(pre[0] == in[i])                break;        }        if(i == inlen)            return NULL;        vector<int> preLeft;        vector<int> inLeft;        vector<int> preRight;        vector<int> inRight;        for(int j = 0; j < i;j++){            inLeft.push_back(in[j]);            preLeft.push_back(pre[j+1]);        }        for(int j = i+1; j < inlen;j++){            inRight.push_back(in[j]);            preRight.push_back(pre[j]);        }        Root->left = reConstructBinaryTree(preLeft,inLeft);        Root->right = reConstructBinaryTree(preRight,inRight);        return Root;    }