/**
 * 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 {
    static int a=0;
    public void recoverTree(TreeNode root) {
        List<Integer> l1 = new ArrayList<>();
        TreeNode r2 = root;
        trvrs(r2,l1);
//        System.out.println(l1);
        Collections.sort(l1);
 //       System.out.println(l1);
        recover(root,l1);
    }
    public static void trvrs(TreeNode root, List<Integer> l)
    {
        if(root==null) return ;
        trvrs(root.left,l);
        l.add(root.val);
        trvrs(root.right,l);
    }
    public static void recover(TreeNode root, List<Integer> l)
    {
        if(root==null) return ;
        recover(root.left,l);
        if(root!=null && root.val != l.get(a))
        {
  //          System.out.println(root.val+"   ___    "+l.get(a));
            root.val = l.get(a);
            a++;
        }else{
            a++;
        }
        recover(root.right,l);
    }
}