/**

 * Definition for singly-linked list.

 * struct ListNode {

 *     int val;

 *     ListNode *next;

 *     ListNode(int x) : val(x), next(NULL) {}

 * };

 */

/**

 * Definition for a binary tree node.

 * struct TreeNode {

 *     int val;

 *     TreeNode *left;

 *     TreeNode *right;

 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}

 * };

 */

class Solution {

public:

    vector<int> v;

    TreeNode* sortedListToBST(ListNode* head) {
　　　　//遍历链表将值存入vector中，方便之后的查中间值操作。

        while(head!=NULL)

        {

            v.push_back(head->val);

            head=head->next;

        }

    return  dfs(,v.size()-);

    }

    TreeNode * dfs(int l,int r)

    {

        if(l>r) return NULL;

        int mid=l+(r-l)/;

        TreeNode *root=new TreeNode(v[mid]);

        root->left=dfs(l,mid-);

        root->right=dfs(mid+,r);

        return root;

    }

};