Closest Binary Search Tree Value

Given a non-empty binary search tree and a target value, find the value in the BST that is closest to the target.

Note:

Given target value is a floating point. You are guaranteed to have only one unique value in the BST that is closest to the target.

Solution

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Solution {
     public int closestValue(TreeNode root, double target) {
        int[] closest = new int[1];
        double[] diff = new double[1];
        diff[0] = Double.MAX_VALUE;

        traverse(root, closest, diff, target);
        return closest[0];
    }

    private void traverse(TreeNode root, int[] closest, double[] diff, double target) {
        if (root == null) return;

        if (Math.abs((root.val) - target) < diff[0]) {
            closest[0] = root.val;
            diff[0] = Math.abs((double) (root.val) - target);
        }

        if (root.val > target) {
            traverse(root.left, closest, diff, target);
        } else {
            traverse(root.right, closest, diff, target);
        }
    }
}