Leetcode-Populating Next Right Pointer in Binary Tree II
Follow up for problem "Populating Next Right Pointers in Each Node".
What if the given tree could be any binary tree? Would your previous solution still work?
Note:
- You may only use constant extra space.
For example,
Given the following binary tree,
1
/ \
2 3
/ \ \
4 5 7
After calling your function, the tree should look like:
1 -> NULL
/ \
2 -> 3 -> NULL
/ \ \
4-> 5 -> 7 -> NULL
Solution:
/**
* Definition for binary tree with next pointer.
* public class TreeLinkNode {
* int val;
* TreeLinkNode left, right, next;
* TreeLinkNode(int x) { val = x; }
* }
*/
public class Solution {
public void connect(TreeLinkNode root) {
if (root==null)
return; root.next = null;
TreeLinkNode levelHead = root; while (true){
boolean hasChild = false;
TreeLinkNode cur = levelHead;
TreeLinkNode nextLevelPre = null;
TreeLinkNode nextLevelHead = null;
while (cur!=null){
if (cur.left!=null){
hasChild = true;
if (nextLevelPre!=null){
nextLevelPre.next = cur.left;
nextLevelPre = cur.left;
} else {
nextLevelPre = cur.left;
nextLevelHead = cur.left;
}
} if (cur.right!=null){
hasChild = true;
if (nextLevelPre!=null){
nextLevelPre.next = cur.right;
nextLevelPre = cur.right;
} else {
nextLevelPre = cur.right;
nextLevelHead = cur.right;
}
} cur = cur.next;
}
if (hasChild)
nextLevelPre.next = null; //If reach the last level, then stop.
if (!hasChild)
break; //Move to next level.
levelHead = nextLevelHead;
} return;
}
}
At each level, after we construct the link list, we have a linked list to visit all nodes in this level. Then we can visit all child nodes in the next level along this linked list.This is a very smart way.
Note: For this question, we need to be careful about where the first child node in the next level is.
Leetcode-Populating Next Right Pointer in Binary Tree II的更多相关文章
- [Leetcode] Populating next right pointer in each node ii 填充每个节点的右指针
Follow up for problem "Populating Next Right Pointers in Each Node". What if the given tre ...
- LeetCode: Populating Next Right Pointer in Each Node
LeetCode: Populating Next Right Pointer in Each Node Given a binary tree struct TreeLinkNode { TreeL ...
- 【一天一道LeetCode】#104. Maximum Depth of Binary Tree
一天一道LeetCode 本系列文章已全部上传至我的github,地址:ZeeCoder's Github 欢迎大家关注我的新浪微博,我的新浪微博 欢迎转载,转载请注明出处 (一)题目 来源:http ...
- 【LeetCode】297. Serialize and Deserialize Binary Tree 解题报告(Python)
[LeetCode]297. Serialize and Deserialize Binary Tree 解题报告(Python) 标签: LeetCode 题目地址:https://leetcode ...
- 【LeetCode】662. Maximum Width of Binary Tree 解题报告(Python)
[LeetCode]662. Maximum Width of Binary Tree 解题报告(Python) 标签(空格分隔): LeetCode 题目地址:https://leetcode.co ...
- [LeetCode] Verify Preorder Serialization of a Binary Tree 验证二叉树的先序序列化
One way to serialize a binary tree is to use pre-oder traversal. When we encounter a non-null node, ...
- LeetCode Verify Preorder Serialization of a Binary Tree
原题链接在这里:https://leetcode.com/problems/verify-preorder-serialization-of-a-binary-tree/ 题目: One way to ...
- [LeetCode] Lowest Common Ancestor of a Binary Tree 二叉树的最小共同父节点
Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree. According ...
- LeetCode之104. Maximum Depth of Binary Tree
-------------------------------- 递归遍历即可 AC代码: /** * Definition for a binary tree node. * public clas ...
随机推荐
- C# 可否对内存进行直接的操作?
可以,用 unsafe.用的时候记得在项目属性(Properties)->生成(Build)->常规(General)中钩上允许不安全代码 (Allow unsafe code).否则会出 ...
- setTime
var getTime = function() { var _ = ['00', '01', '02', '03', '04', '05', '06', '07', '08', '09'], //补 ...
- keystone WSGI流程
作为OpenStack两种基本的通信方式(RESTful API与消息总线)之中的一个.理解RESTful API的设计思路和运行过程,有助于我们对OpenStack有更好的理解.RESTful仅仅是 ...
- atitit.session的原理以及设计 java php实现的异同
atitit.session的原理以及设计 java php实现的异同 1. session的保存:java在内存中,php脚本因为不能常驻内存,所以在文件中 1 2. php的session机制 1 ...
- PCIe学习笔记(15)--- TLP的ROUTING方式
PCIE是POINT TO POINT的,不像PCI,是SHARED-BUS,总线上的数据,是被所有EP DEV看到的. 这一点与USB2.0比较类似,是广播方式的(BROADCASTING) USB ...
- redis命令_SETNX
SETNX key value 将 key 的值设为 value ,当且仅当 key 不存在. 若给定的 key 已经存在,则 SETNX 不做任何动作. SETNX 是『SET if Not eXi ...
- windows server 2003下搭建amp环境
参考: http://blog.csdn.net/binyao02123202/article/details/7578914 http://4359260.blog.51cto.com/434926 ...
- vue 过渡效果-列表过渡
到目前为止,关于过渡我们已经讲到, 单个节点 同一时间渲染多个节点的一个 那么怎么同时渲染整个列表,比如使用v-if?在这种场景下,使用<transition-group>组件,在我们深入 ...
- 阿里正式发布《Java开发手册》终极版!
摘要: 本文讲的是阿里正式发布<Java开发手册>终极版!,别人都说我们是码农,但我们知道,自己是个艺术家.也许我们不过多在意自己的外表和穿着,但我们不羁的外表下,骨子里追求着代码的美.质 ...
- 初窥XSS跨站脚本攻击
XSS跨站脚本攻击的分类 一. 反射型XSS跨站脚本攻击 二. 存储型XSS跨站脚本攻击 三. 基于DOM的XSS跨站脚本攻击 1.反射性XSS 经过后端,不经过数据库 2.储存型XSS 经过后端,经 ...