YuanTheCoder的博客

Intro to Dynamic Programming 动态规划专题 [1]

YuanTheCoder — Wed, 28 Aug 2019 00:59:56 +0800

1 动态规划简介动态规划在查找有很多重叠子问题的情况的最优解时有效。它将问题重新组合成子问题。为了避免多次解决这些子问题，它们的结果都逐渐被计算并被保存，从简单的问题直到整个问题都被解决。因此，动态规划保存递归时的结果，因而不会在解决同样的问题时花费时间。动态规划只能应用于有最优子结构的问题。最优子结构的意思是局部最优解能决定全局最优解（对有些问题这个要求并不能完全满足，故有时需要引入一定的近...

Java Map/Collections 的使用场景

YuanTheCoder — Mon, 26 Aug 2019 10:35:37 +0800

原文链接： http://www.sergiy.ca/guide-to-selecting-appropriate-map-collection-in-java

Generics in Java, Java generics 的使用

YuanTheCoder — Mon, 26 Aug 2019 10:29:26 +0800

Generics in Java, Java generics 的使用 1 Introduction to generics Generics are a way to tell a compiler what type of object a collection can contain. The idea is to allow type (Integer, String, … etc an...

Leetcode 38. Count and Say Java解法

YuanTheCoder — Sat, 24 Aug 2019 23:19:18 +0800

The count-and-say sequence is the sequence of integers with the first five terms as following: 1. 1 2. 11 3. 21 4. 1211 5. 111221 1is read off as"one 1"or11.11is read off ...

leetcode 70. Climbing Stairs Java解法，Amazon面试

YuanTheCoder — Thu, 22 Aug 2019 10:39:58 +0800

You are climbing a stair case. It takesnsteps to reach to the top. Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top? Note:Givennwill be a positive...

Leetcode 250. Count Univalue Subtrees 谷歌面试, Java解法详解

YuanTheCoder — Thu, 22 Aug 2019 10:19:58 +0800

这是一道谷歌会考的题目 Given a binary tree, count the number of uni-value subtrees. A Uni-value subtree means all nodes of the subtree have the same value. Example : Input: root = [5,1,5,5,5,null,5] ...

Java 简单Project 2, 学生数据库

YuanTheCoder — Wed, 21 Aug 2019 05:08:35 +0800

任务描述实现： package com.company; import java.util.Scanner; public class Main { public static void main(String[] args) { // ask how many students we want to add System.out.prin...

狗家 Online Assessment

YuanTheCoder — Thu, 08 Aug 2019 23:57:26 +0800

License Key Formatting Unique Email Addresses Fruit Into Baskets Odd Even Jump Maximum Area Serving Cake Min Days to Bloom Fill Matrix Compare Strings Largest Subarray Length K Decreasing Sub...

IntelliJ Idea, Java8 连接 MySQL 之方法Windows

YuanTheCoder — Sun, 04 Aug 2019 23:52:56 +0800

1. 准备条件安装Java, 我的安装版本是Java 8. 安装MySQL，我的安装版本是 MySQL 8.0.15, 到官网下载安装即可，一路点默认的选项，下一步。安装完成后需要添加到PATH. 还要在MySQL 额外下载一个connector, 根据自己安装的版本下载，我的是mysql-connector-java-8.0.15.jar。然后把connector 的jar...

Java 简单Project 1, 命令行程序

YuanTheCoder — Sat, 03 Aug 2019 11:19:49 +0800

1. 命令行程序利用main函数可以接受参数 String[] args 这一特点。 public static void main(String[] args) 2. 任务描述写一个命令行程序，能够 1. 读取一个目录下的所有文件和子目录 2. 在每个文件中寻找一段文本，支持正则查找 3. 把所有符合条件的文件添加到一个ZIP压缩包。 3. 逐步分析 3.1 首先，我...

Java中 Queue队列的用法及例子

YuanTheCoder — Thu, 01 Aug 2019 22:33:08 +0800

1. Usage 用法 // "static void main" must be defined in a public class. public class Main { public static void main(String[] args) { // 1. Initialize a queue. Queue q...

亚麻 OA 2019 题目

YuanTheCoder — Mon, 29 Jul 2019 23:08:57 +0800

Most Common Word Prison Cells After N Days K Closest Points to Origin Reorder Log Files Partition Labels Min Cost to Add New Roads Min distance to remove the obstacle Roll Dice Min Cost to Con...

Leetcode [141, 142] Linked List Cycle，java解法

YuanTheCoder — Thu, 25 Jul 2019 09:43:24 +0800

141 Linked List Cycle Given a linked list, determine if it has a cycle in it. To represent a cycle in the given linked list, we use an integerposwhich represents the position (0-indexed)in the l...

Leetcode[217, 136, 349, 202] HashTable 小专题 1 HashSet

YuanTheCoder — Sun, 21 Jul 2019 15:43:27 +0800

HashTableis a data structure which organizes data usinghash functionsin order to supportquick insertion and search.In this article, we will take a look at the principle of the hash table. 一自己定...

Leetcode 1089. Duplicate Zeros, java解法及Queue的使用

YuanTheCoder — Sat, 20 Jul 2019 17:21:58 +0800

Given a fixed lengtharrayarrof integers, duplicate each occurrence of zero, shifting the remaining elements to the right. Note that elements beyond the length of the original array are not written...

Leetcode[498, 54, 118 ] Array 专题（2） 2D Array

YuanTheCoder — Fri, 19 Jul 2019 11:51:34 +0800

此类题目就是花式遍历2维数组，我个人并不喜欢。 498.Diagonal Traverse Given a matrix of M x N elements (M rows, N columns), return all elements of the matrix in diagonal order as shown in the below image. Example: I...

Leetcode 283. Move Zeroes java解法

YuanTheCoder — Tue, 16 Jul 2019 08:58:48 +0800

Given an arraynums, write a function to move all0's to the end of it while maintaining the relative order of the non-zero elements. Example: Input: [0,1,0,3,12] Output: [1,3,12,0,0] Note: You m...

Leetcode 1119. Remove Vowels from a String, Java解法

YuanTheCoder — Mon, 15 Jul 2019 23:52:40 +0800

Given a stringS, remove the vowels'a','e','i','o', and'u'from it, and return the new string. Example 1: Input: "leetcodeisacommunityforcoders" Output: "ltcdscmmntyfrcdrs" Example 2: Inpu...

Leetcode [724, 747,66] Array专题 (1)

YuanTheCoder — Mon, 15 Jul 2019 13:12:46 +0800

Operations in Array // "static void main" must be defined in a public class. public class Main { public static void main(String[] args) { // 1. Initialize int[] a0 = new int[5]; ...

Leetcode 867. Transpose Matrix, Java解法

YuanTheCoder — Sun, 14 Jul 2019 21:11:57 +0800

Given amatrixA, return the transpose ofA. The transpose of a matrix is the matrix flipped over it's main diagonal, switching the row and column indices of the matrix. Example 1: Input: [[1,2,3]...