二叉树的镜像

public class Solution {
    public void Mirror(TreeNode root) {
        if(root == null ||(root.left == null && root.right == null)){
            return;
        }
        TreeNode tem = root.left;
        root.left = root.right;
        root.right = tem;
        if(root.left != null){
            Mirror(root.left);
        }
        if(root.right != null){
            Mirror(root.right);
        }
    }
}