1 public class Solution {
 2     int time = 0;
 3     TreeNode KthNode(TreeNode root, int k){
 4         if(root==null) return null;
 5         TreeNode node =  KthNode(root.left,k);
 6         if(node!=null) return node;
 7         time++;
 8         if(time==k)
 9             return root;
10         node =  KthNode(root.right,k);
11           return node;
12         
13     }
14 
15 }