Given an integer array
nums where the elements are sorted in ascending order, convert it to a height-balanced binary search tree.
A height-balanced binary tree is a binary tree in which the depth of the two subtrees of every node never differs by more than one.
Input: nums = [-10,-3,0,5,9]
Explanation: [0,-10,5,null,-3,null,9] is also accepted:
Input: nums = [1,3]
Explanation: [1,3] and [3,1] are both a height-balanced BSTs.
1 <= nums.length <= 104
-104 <= nums[i] <= 104
numsis sorted in a strictly increasing order.