递归就好,比如root节点,交换左右子树,然后对于左右子树,再各自交换对应的左右子树
不过这些代码都是inplace的不要返回状态
# -*- 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 == None:
return
root.left,root.right = root.right,root.left
if(root.left):
self.Mirror(root.left)
if(root.right):
self.Mirror(root.right)
java代码
/**
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) {
TreeNode tmp = new TreeNode(0);
if(root == null){
return;
}
tmp = root.left;
root.left = root.right;
root.right = tmp;
if(root.left!=null){this.Mirror(root.left);}
if(root.right!=null){this.Mirror(root.right);}
}
}