JZ18 - 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

解题思路

• 递归 python/JS

# -*- 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
        self.Mirror(root.left)
        self.Mirror(root.right)
        return root

/* function TreeNode(x) {
    this.val = x;
    this.left = null;
    this.right = null;
} */
function Mirror(root)
{
    if(root == null){
        return;
    }
    var temp = root.left;
    root.left = root.right;
    root.right = temp;
    Mirror(root.left);
    Mirror(root.right);
}

• BFS做法

# -*- coding:utf-8 -*-
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
class Solution:
    def Mirror(self, root):
        # write code here
        q = [root]
        while q:
            curNode = q.pop(0)
            if not curNode:
                return None
            if curNode.left:
                q.append(curNode.left)
            if curNode.right:
                q.append(curNode.right)
            curNode.left, curNode.right = curNode.right, curNode.left