<p>Given an integer array <code>nums</code> where the elements are sorted in <strong>ascending order</strong>, convert <em>it to a </em><span data-keyword="height-balanced"><strong><em>height-balanced</em></strong></span> <em>binary search tree</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/02/18/btree1.jpg" style="width: 302px; height: 222px;" />
<pre>
<strong>Input:</strong> nums = [-10,-3,0,5,9]
<strong>Output:</strong> [0,-3,9,-10,null,5]
<strong>Explanation:</strong> [0,-10,5,null,-3,null,9] is also accepted:
<img alt="" src="https://assets.leetcode.com/uploads/2021/02/18/btree2.jpg" style="width: 302px; height: 222px;" />
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/02/18/btree.jpg" style="width: 342px; height: 142px;" />
<pre>
<strong>Input:</strong> nums = [1,3]
<strong>Output:</strong> [3,1]
<strong>Explanation:</strong> [1,null,3] and [3,1] are both height-balanced BSTs.
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= nums.length &lt;= 10<sup>4</sup></code></li>
	<li><code>-10<sup>4</sup> &lt;= nums[i] &lt;= 10<sup>4</sup></code></li>
	<li><code>nums</code> is sorted in a <strong>strictly increasing</strong> order.</li>
</ul>

class Solution 
{
public:
    void insert(TreeNode* root, int val)
    {
        if (!root)
            return;
        if (val > root->val)
        {
            if (!root->right)
            {
                TreeNode* node = new TreeNode(val);
                root->right = node;
                return;
            }
            else
            {
                insert(root->right, val);
            }
        }
        else
        {
            if (!root->left)
            {
                TreeNode* node = new TreeNode(val);
                root->left = node;
                return;
            }
            else
            {
                insert(root->left, val);
            }
        }
        return;
    }
    TreeNode* root;
    void rec(vector<int> nums, int start, int end)
    {
        if (start > end)
            return;
        int mid = (start + end) / 2;
        insert(root, nums[mid]);
        rec(nums, start, mid - 1);
        rec(nums, mid + 1, end);
    }
    TreeNode* sortedArrayToBST(vector<int>& nums)
    {
        root = new TreeNode;
        root->val = nums[nums.size() / 2];
        rec(nums, 0, nums.size() / 2 - 1);
        rec(nums, nums.size() / 2 + 1, nums.size() - 1);
        return root;
    }
};
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