LeetCode-in-Java
783. Minimum Distance Between BST Nodes
Easy
Given the root of a Binary Search Tree (BST), return the minimum 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, 100]. 0 <= Node.val <= 105
Note: This question is the same as 530: https://leetcode.com/problems/minimum-absolute-difference-in-bst/
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 prev = -1;
private int min = Integer.MAX_VALUE;
public int minDiffInBST(TreeNode root) {
if (root == null) {
return min;
}
minDiffInBST(root.left);
if (prev != -1) {
min = Math.min(min, Math.abs(root.val - prev));
}
prev = root.val;
minDiffInBST(root.right);
return min;
}
}