/**
public class TreeNode {
int val = 0;
TreeNode left = null;
TreeNode right = null;
public TreeNode(int val) {
this.val = val;
}
}
*/
public class Solution {
public void Mirror(TreeNode root) {
if(root==null) return;
if(root.left==null&&root.right==null) return;
TreeNode treeNode=root.left;
root.left=root.right;
root.right=treeNode;
if(root.left!=null)
Mirror(root.left);
if(root.right!=null)
Mirror(root.right);
}
}