Prompt

Node Depths
The distance between a node in a Binary Tree and the tree’s root is called the node’s depth. Write a function that takes in a Binary Tree and returns the sum of its nodes’ depths.

Each BinaryTree node has an integer value , a left child node, and a right child node. Children nodes can either be BinaryTree nodes themselves or None / null .

Sample Input

Sample Output

Solution 1

import java.util.*;class Program {// Average case: when the tree is balanced// O(n) time | O(h) space - where n is the number of nodes in// the Binary Tree and h is the height of the Binary Tree.public static int nodeDepths(BinaryTree root) {int sumOfDepth = 0;//AList<Level> stack = new ArrayList<Level>();//Bstack.add(new Level(root,0));while (stack.size() > 0) {//CLevel top = stack.remove(stack.size() - 1);BinaryTree node = top.root;int depth = top.depth;if (node == null) continue;sumOfDepth += depth;stack.add(new Level(node.left, depth + 1));stack.add(new Level(node.right, depth + 1));}return sumOfDepth;}static class Level {public BinaryTree root;int depth;public Level(BinaryTree root, int depth) {this.root = root;this.depth = depth;}}static class BinaryTree {int value;BinaryTree left;BinaryTree right;public BinaryTree(int value) {this.value = value;left = null;right = null;}}
}

# 1A

一定要初始化

# 1B

用简单的数组+stack的思想

# 1C

length、size、size()

Solution 2

import java.util.*;class Program {// Average case: when the tree is balanced// O(n) time | O(h) space - where n is the number of nodes in// the Binary Tree and h is the height of the Binary Tree.public static int nodeDepths(BinaryTree root) {return nodeDepthsHelper(root, 0);}public static int nodeDepthsHelper(BinaryTree root, int depth) {if (root == null) return 0;return depth + nodeDepthsHelper(root.left, depth + 1) + nodeDepthsHelper(root.right, depth + 1);}static class BinaryTree {int value;BinaryTree left;BinaryTree right;public BinaryTree(int value) {this.value = value;left = null;right = null;}}
}

Node Depths相关推荐

LeetCode19. Remove Nth Node From End of List 删除链表中的倒数第n个位置的元素
前言本文是LeetCode19. Remove Nth Node From End of List解法,这个题目需要删除链表中的倒数第n个位置的元素代码 # -*- coding: utf-8 - ...
Node.js 简单入门
目录一. 什么是Nodejs 二. Nodejs组成图(对比jdk) 三. Nodejs的安装四. 第一个Nodejs程序五. Node实现请求响应六. Node操作MYSQL数据库 1. 安 ...
CentOS7的node.js安装
一.方式1:yum安装这里我们指定安装8.x以上的版本 curl --silent --location https://rpm.nodesource.com/setup_8.x | sudo ba ...
Node搭建多人聊天室
博客初期准备使用的通讯,后被荒废. 使用的是nodejs-websocket,未使用socket.io 用来玩玩的东西,了解下通讯协议. 演示地址:socket.amayaliu.cn git地址:h ...
node.js（四）小结
用之前的内容写一个简单的注册登录 const http = require('http') const urlLib = require('url') const fs = require('fs') ...
node.js(node.js+mongoose小案例)_实现简单的注册登录退出
一.前言通过node.js基本知识对node.js基本知识的一个简单应用 1.注册 2.登录 3.退出二.基本内容 1.项目结构搭建如图所示 2.这个小案列中用到了art-template子模板以 ...
node、Mongo项目如何前后端分离提供接口给前端
node接口编写,vue-cli代理接口方法通常前端使用的MocK 数据的方法,去模拟假的数据,但是如果有node Mongodb 去写数据的话就不需要在去mock 数据了,具体的方法如下. 首先 ...
linux安装语言总是waiting,node的serialport在arm的Linux安装血泪史之我太难了
0.序本人在arm的Linux系统上serialport耗时5天,现在想想都头皮发麻! 下面我简单说一下过程,由于error时没有截图留档,关于出现的error,我就用语言描述一下,要是有什么不理解 ...
Virtual host / experienced an error on node rabbit@wohu-rabbit and may be inaccessible
RabbitMQ 如下错误: Virtual host / experienced an error on node rabbit@wohu-rabbit and may be inaccessibl ...

Node Depths