二叉树的镜像

package demo;import java.util.Stack;/* * 题目描述操作给定的二叉树，将其变换为源二叉树的镜像。输入描述:二叉树的镜像定义：源二叉树             8           /  \          6   10         / \  / \        5  7 9 11        镜像二叉树            8           /  \          10   6         / \  / \        11 9 7  5 */public class Offer_38 {    public void Mirror(TreeNode root) {        //所谓镜像，就是左右子树交换位置        if(root == null)            return;//若为空则直接返回        Stack<TreeNode> stack = new Stack<TreeNode>();//新建一个栈空间        stack.push(root);//将给定树入栈        while(!stack.empty()) {//若栈不为空            TreeNode node = stack.pop();//将出栈数据保存在新建的node中            if(node.left != null || node.right != null) {//若node左右均不为空                TreeNode nodeLeft = node.left;//新建左右TreeNode节点                TreeNode nodeRight = node.right;                node.left = nodeRight;//交换左右节点                node.right = nodeLeft;            }            if(node.left != null)//若左右节点不为空则入栈                stack.push(node.left);            if(node.right != null)                stack.push(node.right);        }    }    public static void main(String[] args) {        Offer_38 off = new Offer_38();        TreeNode root = new TreeNode(1);        root.left = new TreeNode(6);        root.right = new TreeNode(10);        root.left.left = new TreeNode(5);        root.left.right = new TreeNode(7);        root.right.left = new TreeNode(9);        root.right.right = new TreeNode(11);    }}