LeetCode@DFS_257_Binary_Tree_Paths

Problem:

Given an array where elements are sorted in ascending order, convert it to a height balanced BST.

Java:

/** * Definition for a binary tree node. * public class TreeNode { *     int val; *     TreeNode left; *     TreeNode right; *     TreeNode(int x) { val = x; } * } */public class Solution {  public TreeNode sortedArrayToBST(int[] nums){if (nums == null){return null;}TreeNode ans = helper(nums, 0, nums.length-1);return ans;}public TreeNode helper(int[] nums, int start, int end){if (start > end){return null;}int mid = (end + start) / 2;TreeNode root = new TreeNode(nums[mid]);root.left = helper(nums, start, mid - 1);root.right = helper(nums, mid + 1, end);return root;}}