二叉树的镜像

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

思路

第一种思路

镜像的意思就是说将左右子树进行换位，所以直接递归就解决了。

代码

第一种思路

import java.util.LinkedList;
import java.util.Queue;

public class Main {
    public static void main(String[] args) {
        TreeNode root1 = new TreeNode(8);
        TreeNode treeNode1 = new TreeNode(8);
        TreeNode treeNode2 = new TreeNode(7);
        TreeNode treeNode3 = new TreeNode(9);
        TreeNode treeNode4 = new TreeNode(2);
        TreeNode treeNode5 = new TreeNode(4);
        TreeNode treeNode6 = new TreeNode(7);
        root1.left =treeNode1;
        root1.right = treeNode2;
        treeNode1.left = treeNode3;
        treeNode1.right = treeNode4;
        treeNode4.left = treeNode5;
        treeNode4.right = treeNode6;
        Squeue(root1);
        Mirror(root1);
        System.out.println("之后");
        Squeue(root1);
    }
    public static void Mirror(TreeNode root) {
        if(root==null) return;
        else
        {
            TreeNode left = root.left;
            TreeNode right = root.right;
            root.right = left;
            root.left = right;
            Mirror(root.left);
            Mirror(root.right);
        }
    }
    private  static void Squeue(TreeNode root)
    {
        if(root!=null)
        {
            Queue<TreeNode> q = new LinkedList<>();
            q.offer(root);
            while (!q.isEmpty())
            {
                root =  q.poll();
                System.out.print(root.val+"  ");
                if(root.left!=null)
                {
                    q.offer(root.left);
                }
                if(root.right!=null)
                {
                    q.offer(root.right);
                }
            }
        }
    }
}
class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;

    }
}