Leetcode85: 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 {
public:
TreeNode* createTree(vector<int>& nums, int left, int right)
{
if(left>right)
return NULL;
int mid = (right+left)/2;
TreeNode* Node = new TreeNode(nums[mid]);
TreeNode* Nodeleft = createTree(nums, left, mid-1);
TreeNode* Noderight = createTree(nums, mid+1, right);
Node->left = Nodeleft;
Node->right = Noderight;
return Node;
}
TreeNode* sortedArrayToBST(vector<int>& nums) {
return createTree(nums, 0, nums.size()-1);
}
};