Given a sorted integer array input_array in strictly increasing order, construct a height-balanced binary search tree (BST) from input_array. Return the root node of the BST. The BST should be height-balanced, meaning the depths of the two subtrees of every node differ by no more than one. For testing purposes, represent the tree as a level-order traversal list, where null represents missing children.
Example 1
Input: [2,4,7,11,15]
Output: [7,4,15,2,null,11]
Explanation: A possible height-balanced BST is: root 7, left child 4, right child 15, left child of 4 is 2, right child of 15 is 11.
Example 2
Input: [5,8]
Output: [8,5]
Explanation: A possible height-balanced BST is: root 8, left child 5.
Constraints
Case 1
Input: [1,2,3,4,5,6]
Expected: [4,2,6,1,3,5]
Case 2
Input: [10,20,30]
Expected: [20,10,30]
Case 3
Input: [0]
Expected: [0]
Case 4
Input: [-5,-2,0,3,8]
Expected: [0,-2,8,-5,null,3]