// @Title: 二叉搜索树节点最小距离 (Minimum Distance Between BST Nodes)
// @Author: qisiii
// @Date: 2024-09-16 15:43:41
// @Runtime: 1 ms
// @Memory: 40.3 MB
// @comment: 
// @flag: 
/**
 * 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 {
    public int minDiffInBST(TreeNode root) {
        List<Integer> list=new ArrayList<>();
        dfs(root,list);
        int result=list.get(1)-list.get(0);
        for(int i=2;i<list.size();i++){
            result=Math.min(result,list.get(i)-list.get(i-1));
        }
        return result;
    }
    private void dfs(TreeNode root,List<Integer> list){
        if(root==null){
            return;
        }
        dfs(root.left,list);
        list.add(root.val);
        dfs(root.right,list);
    }
}