LeetCode--Convert Sorted Array to Binary Search Tree

Given an array where elements are sorted in ascending order, convert it to a height balanced BST.

/** * 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 *sortedArrayToBST(vector<int> &num)     {        int n=num.size();        if(n==0)            return NULL;        if(n==1)            return new TreeNode(num[0]);        return sortedArrayToBST(num,0,n-1);    }    TreeNode *sortedArrayToBST(vector<int> &num, int low, int high)     {        if(low>high)            return NULL;        if(low == high)        {            return new TreeNode(num[low]);        }        int mid = (low+high)/2;        TreeNode* root = new TreeNode(num[mid]);        root->left = sortedArrayToBST(num,low,mid-1);        root->right = sortedArrayToBST(num,mid+1,high);        return root;    }};