/**
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 node = root.left;
root.left = root.right;
root.right = node;
if(root.left!=null){Mirror(root.left);}
if(root.right!=null){Mirror(root.right);}
}
}