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。

/** * Definition for binary tree * struct TreeNode { *     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */class Solution {public:    TreeNode* reConstructBinaryTree(vector
       
         pre,vector
        
          vin) {        int vinSize = vin.size();        if(vinSize == 0) return NULL;        vector
         
          pre_left,pre_right,vin_left,vin_right;        int val = pre[0];        int i;        for(i = 0; i < vinSize; i ++) {            if(vin[i] == val){                break;            }        }        int index = i;        TreeNode* tree = new TreeNode(val);        for(i = 0; i < vinSize; i++ ) {            if(i < index) {                vin_left.push_back(vin[i]);                pre_left.push_back(pre[i+1]);            } else if(i > index) {                vin_right.push_back(vin[i]);                pre_right.push_back(pre[i]);            }        }        tree->left = reConstructBinaryTree(pre_left,vin_left);        tree->right = reConstructBinaryTree(pre_right,vin_right);        return tree;    }    };