C++重建二叉树

  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<int> pre,vector<int> vin) {
        int vinlen=vin.size();
        if(vinlen==0) return NULL;
        vector<int> leftpre,rightpre,leftvin,rightvin;
        TreeNode* head=new TreeNode(pre[0]);
        int root=0;
        for(int i=0;iif(vin[i]==pre[0]){
                root=i;
                break;
            }
        for(int i=0;i1]);
            leftvin.push_back(vin[i]);
        }
        for(int i=root+1;ileft=reConstructBinaryTree(leftpre,leftvin);
        head->right=reConstructBinaryTree(rightpre,rightvin);
        return head;
    }
};