Source: leetcode 108. Convert Sorted Array to Binary Search Tree
Q. Given an array where elements are sorted in ascending order, convert it to a height balanced BST.
Answer
Convert Sorted Array to Binary Search Tree
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/**
* Definition for a binary tree node.
* function TreeNode(val) {
* this.val = val;
* this.left = this.right = null;
* }
*/
/**
* @param {number[]} nums
* @return {TreeNode}
*/
export default function sortedArrayToBST (nums) {
if (!nums.length) return null
function helper(nums, low, high) {
if (low > high) {
return null
}
const mid = (low + high) / 2 | 0
const node = new TreeNode(nums[mid])
node.left = helper(nums, low, mid - 1)
node.right = helper(nums, mid + 1, high)
return node;
}
return helper(nums, 0, nums.length - 1)
}