108. Convert Sorted Array to Binary Search Tree lnk

//https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree/
/**
 * 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 {
private:
    TreeNode* sortedArrayBST(const vector<int>& nums, int cur){
        if(cur == nums.size()) return NULL;
        //int m = l+(h-l)/2;
        int val = nums[cur];
        TreeNode *root = new TreeNode(val);
       // root->left = NULL;
        root->right = sortedArrayBST(nums,cur+1);
        return root;
    }
public:
    TreeNode* sortedArrayToBST(vector<int>& nums) {
        return sortedArrayBST(nums, 0);
    }
};