根据二叉树的前序遍历和中序遍历重建二叉树

 1 /**
 2  * Definition for binary tree
 3  * struct TreeNode {
 4  *     int val;
 5  *     TreeNode *left;
 6  *     TreeNode *right;
 7  *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 8  * };
 9  */ 
10 
11    struct TreeNode* reConstructBinaryTree(vector<int> pre,vector<int> in) {
12         if(pre.size()==0||in.size()==0)
13         {
14             return NULL;
15         }    
16         if(pre.size()==1)
17         {
18             return new TreeNode(pre.front());
19         }        
20         if(in.size()==1)
21         {
22             return new TreeNode(in.front());
23         }
24         int node_Val=pre.front();//用来存根节点的值
25         auto node_in=find(in.begin(),in.end(),node_Val);//根节点在in的位置
26         
27         //左子树区间
28         vector<int> left_in_Block(in.begin(),node_in);
29         int move=node_in-in.begin();
30         vector<int> left_pre_Block(++pre.begin(),pre.begin()+move+1);
31         
32         //右子树区间
33         vector<int> right_in_Block(++node_in,in.end());
34         vector<int> right_pre_Block(pre.begin()+move+1,pre.end());
35         
36         TreeNode *node=new TreeNode(node_Val);//根节点
37         node->left=reConstructBinaryTree(left_pre_Block,left_in_Block);
38         node->right=reConstructBinaryTree(right_pre_Block,right_in_Block);
39         return node;
40     }