LeetCode-in-Java
530. Minimum Absolute Difference in BST
Easy
Given the root of a Binary Search Tree (BST), return the minimum absolute difference between the values of any two different nodes in the tree.
Example 1:
Input: root = [4,2,6,1,3]
Output: 1
Example 2:
Input: root = [1,0,48,null,null,12,49]
Output: 1
Constraints:
- The number of nodes in the tree is in the range
[2, 104]. 0 <= Node.val <= 105
Note: This question is the same as 783: https://leetcode.com/problems/minimum-distance-between-bst-nodes/
Solution
import com_github_leetcode.TreeNode;
/*
* 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;
* }
* }
*/
public class Solution {
private int ans = Integer.MAX_VALUE;
private int prev = Integer.MAX_VALUE;
public int getMinimumDifference(TreeNode root) {
if (root == null) {
return ans;
}
getMinimumDifference(root.left);
ans = Math.min(ans, Math.abs(root.val - prev));
prev = root.val;
getMinimumDifference(root.right);
return ans;
}
}