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Convert Sorted Array to Binary Search Tree

EasyP2Coding

Given an integer array nums sorted in ascending order, build a height-balanced binary search tree from it and return its root.

Many balanced trees are valid, so this problem asks for one canonical shape: for the range lo..hi (inclusive), the root is the element at index floor((lo + hi) / 2), which is the left of the two middle elements when the range has even length. Build the left subtree from the part before it and the right subtree from the part after it.

Example 1

Input
nums = [-10,-3,0,5,9]
Output
[0,-10,5,null,-3,null,9]

Example 2

Input
nums = [1,3]
Output
[1,null,3]
Why
The range has two elements, so the left middle (1) becomes the root and 3 is its right child.

Constraints

  • 1 <= nums.length <= 10^4
  • -10^4 <= nums[i] <= 10^4
  • nums is strictly increasing.

Hints

Run checks the 3 visible tests, Submit all 9.