剑指offer-题19：二叉树的镜像

桃扇骨 2022-05-29 03:22 151阅读 0赞

## **题目描述** ##

操作给定的二叉树，将其变换为源二叉树的镜像。

实验平台：[牛客网][Link 1]

--------------------

## **解决思路：** ##

![这里写图片描述][70]

java:

/**
    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;
            } else if (root.left == null && root.right == null) {
                return;
            } else {
                TreeNode tempNode = null;
                tempNode = root.left;
                root.left = root.right;
                root.right = tempNode;
    
                if (root.left != null) {
                    Mirror(root.left);
                }
                if (root.right != null) {
                    Mirror(root.right);
                }
            }
        }
    }

python:

# -*- coding:utf-8 -*-
    # class TreeNode:
    # def __init__(self, x):
    # self.val = x
    # self.left = None
    # self.right = None
    class Solution:
        # 返回镜像树的根节点
        def Mirror(self, root):
            # write code here
            if root is None:
                return
            elif root.left is None and root.right is None:
                return
            else:
                temp = root.left
                root.left = root.right
                root.right = temp
    
                if root.left is not None:
                    self.Mirror(root.left)
                if root.right is not None:
                    self.Mirror(root.right)

[Link 1]: https://www.nowcoder.com/ta/coding-interviews?page=1
[70]: /images/20220529/446e9b02c4b349d79829d2ad0d839d0a.png