Given a non-empty binary search tree and a target value, find the value in the BST that is closest to the target.
Note:
Example:
Input: root = [4,2,5,1,3], target = 3.714286
4
/ 2 5
/ 1 3
Output: 4
binary search
time: O(h), space: O(1) -- h: height of the tree
/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */ class Solution { public int closestValue(TreeNode root, double target) { TreeNode node = root; int min = root.val; while(node != null) { if(Math.abs(node.val - target) < Math.abs(min - target)) { min = node.val; } node = node.val > target ? node.left : node.right; } return min; } }
270. Closest Binary Search Tree Value - Easy
原文：https://www.cnblogs.com/fatttcat/p/10133073.html