LeetCode题解之 Convert Sorted Array to Binary Search Tree

 1 TreeNode* sortedArrayToBST(vector<int>& nums) {
 2         if (nums.size() == 0)
 3             return NULL;
 4         
 5         int left = 0;
 6         int right = nums.size() - 1;
 7         
 8         TreeNode *node = new TreeNode(0);
 9         BST(node->left,nums, left, right);
10         return node->left;
11         
12         
13         
14     }
15     
16     void BST(TreeNode   * &parent, vector<int> &nums,int left, int right)
17     {
18         
19         if (left <= right) {
20             int mid = (left + right)/2;
21             TreeNode *node = new TreeNode(nums[mid]);
22             parent = node;
23             BST(node->left, nums, left, mid - 1);
24             BST(node->right, nums, mid + 1, right);
25         } else {
26             return ;
27         }
28     }