操作给定的二叉树，将其变换为源二叉树的镜像

//方案一：

public class Solution {

public void Mirror(TreeNode root) {
    if(root==null)
        return;
    TreeNode temp=root.left;
    root.left=root.right;
    root.right=temp;
    Mirror(root.left);
    Mirror(root.right);

}

}

//方案二：

import java.util.*;

public class Solution {

public void Mirror(TreeNode root) {
    if(root==null)
        return;

     Stack <TreeNode> stack = new Stack<TreeNode>();
    stack.push(root);

    while(!stack.isEmpty()){
         TreeNode cur=stack.pop();

		if(cur.left!=null||cur.right!=null){
             TreeNode temp=cur.left;
             cur.left=cur.right;
             cur.right=temp;
         }

         if(cur.left!=null)
             stack.push(cur.left);
         if(cur.right!=null)
             stack.push(cur.right);
    }

}

}