LeetCode [270] Closest Binary Search Tree Value

 270. Closest Binary Search Tree Value

Easy

Given the root of a binary search tree and a target value, return the value in the BST that is closest to the target.

 

Example 1:

Input: root = [4,2,5,1,3], target = 3.714286
Output: 4

Example 2:

Input: root = [1], target = 4.428571
Output: 1

 

Constraints:

• The number of nodes in the tree is in the range [1, 104].
• 0 <= Node.val <= 109
• -109 <= target <= 109

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/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode() {} * TreeNode(int val) { this.val = val; } * TreeNode(int val, TreeNode left, TreeNode right) { * this.val = val; * this.left = left; * this.right = right; * } * } */ class Solution { int value = -1; public int closestValue(TreeNode root, double target) { helper(root, target); return value; } void helper(TreeNode node, double target){ if(node==null) return; if(value == -1 || Math.abs(value-target)>Math.abs(node.val-target)){ value = node.val; } if(target<node.val) helper(node.left, target); if(target>node.val) helper(node.right, target); } }