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RSS订阅原创 Git从安装到精通
前言：公司用Git,需要从头学习，下面是教程链接，学习笔记会持续更新在个人分类Git相关里面。教程链接：https://git-scm.com/book/zh/v2
2018-04-11 10:31:22
149
原创 优先队列（堆）
本文将概括性描述优先队列ADT，只对基本的堆数据结构做简要总结，不涉及左式堆，d-堆，斜堆，二项队列等高级数据结构。（算法入门级的总结，欢迎批评指正，根据《数据结构与算法（JAVA语言描述）》一书总结） 优先队列1.模型优先队列是至少支持两种操作的数据结构：insert 与 deleteMin。前者等价于队列中的入队，后者等价于出队。此模型在贪婪算法与外部排序中有较多应用。2.二叉堆二...
2018-02-24 17:39:12
432
原创 Remove Duplicates from Sorted List II
Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.For example,Given 1->2->3->3->4->4->5, return 1->2-&...
2018-02-11 15:14:42
130
原创 Climbing Stairs：动态规划
You are climbing a stair case. It takes n steps 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: Given n will be a positive
2018-02-11 14:33:22
336
原创 树：98. Validate Binary Search Tree
Given a binary tree, determine if it is a valid binary search tree (BST).Assume a BST is defined as follows:The left subtree of a node contains only nodes with keysless than the node's key.The
2018-02-03 17:18:24
126
原创 601. Human Traffic of Stadium
X city built a new stadium, each day many people visit it and the stats are saved as these columns:id, date, peoplePlease write a query to display the records which have 3 or more consecutive rows
2018-01-31 13:58:38
261
原创 262. Trips and Users
The Trips table holds all taxi trips. Each trip has a unique Id, while Client_Id and Driver_Id are both foreign keys to the Users_Id at theUsers table. Status is an ENUM type of (‘completed’, ‘cance
2018-01-31 13:12:42
209
原创 185. Department Top Three Salaries
The Employee table holds all employees. Every employee has an Id, and there is also a column for the department Id.+----+-------+--------+--------------+| Id | Name | Salary | DepartmentId |+----
2018-01-29 16:06:23
326
原创 数据库：184. Department Highest Salary
The Employee table holds all employees. Every employee has an Id, a salary, and there is also a column for the department Id.+----+-------+--------+--------------+| Id | Name | Salary | Department
2018-01-29 15:01:26
360
原创 1.1数组和链表：61. Rotate List（Leetocde）
Given a list, rotate the list to the right by k places, where k is non-negativeExample:Given 1->2->3->4->5->NULL and k = 2,return 4->5->1->2->3->NULL.这道题是我做的比较满意的，因为用到了经验，说一下我自己的解法：大众
2017-11-08 16:19:59
159
原创 1.4字符串：60.Permutation Sequence（Leetocde）
The set [1,2,3,…,n] contains a total of n! unique permutations.By listing and labeling all of the permutations in order,We get the following sequence (ie, for n = 3):"123""132""213""231""312
2017-11-08 15:48:58
249
原创 1.1数组和链表：33. Search in Rotated Sorted Array（Leetcode）
Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand.(i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2).You are given a target value to search. If foun
2017-11-07 13:39:15
118
原创 1.1数组和链表：19. Remove Nth Node From End of List(Leetcode)
Given a linked list, remove the nth node from the end of list and return its head.题目大意：给定一个链表，删除它倒数第n位的节点并重新返回此链表博主想到的方法比较简单，先遍历一次求出链表的长度，确定是正数第几个节点被删除，然后二次遍历删除它方法一：class Solution { publ
2017-11-07 11:20:11
134
原创 197. Rising Temperature(Lettcode）
Given a Weather table, write a SQL query to find all dates' Ids with higher temperature compared to its previous (yesterday's) dates.+---------+------------+------------------+| Id(INT) | Date(DA
2017-11-05 16:39:25
203
原创 196. Delete Duplicate Emails
Write a SQL query to delete all duplicate email entries in a table named Person, keeping only unique emails based on its smallest Id.+----+------------------+| Id | Email |+----+-----
2017-11-05 15:59:52
212
转载 1.1数组和链表：189. Rotate Array（Leetcode）
Rotate an array of n elements to the right by k steps.For example, with n = 7 and k = 3, the array [1,2,3,4,5,6,7] is rotated to [5,6,7,1,2,3,4].Note:Try to come up as many solutions as yo
2017-11-05 14:54:10
157
转载 SQL中distinct的用法
转载至 http://www.cnblogs.com/rainman/archive/2013/05/03/3058451.html在表中，可能会包含重复值。这并不成问题，不过，有时您也许希望仅仅列出不同（distinct）的值。关键词 distinct用于返回唯一不同的值。表A：表B:1.作用于单列select distinct name
2017-11-03 15:09:40
4368
原创 182. Duplicate Emails（Lettcode）
Write a SQL query to find all duplicate emails in a table named Person.+----+---------+| Id | Email |+----+---------+| 1 | [email protected] || 2 | [email protected] || 3 | [email protected] |+----+---------+For
2017-11-03 14:56:45
163
原创 181. Employees Earning More Than Their Managers(Lettcode)
The Employee table holds all employees including their managers. Every employee has an Id, and there is also a column for the manager Id.+----+-------+--------+-----------+| Id | Name | Salary |
2017-11-03 14:18:53
156
转载 176. Second Highest Salary（Leetcode)
文章出处：http://www.cnblogs.com/grandyang/p/5348961.htmlWrite a SQL query to get the second highest salary from the Employee table.+----+--------+| Id | Salary |+----+--------+| 1 | 100 || 2
2017-11-03 13:05:53
243
转载 MySQL多表查询
1、内联接（典型的联接运算，使用像 = 或 <> 之类的比较运算符）。包括相等联接和自然联接。 内联接使用比较运算符根据每个表共有的列的值匹配两个表中的行。例如，检索 students和courses表中学生标识号相同的所有行。2、外联接。外联接可以是左向外联接、右向外联接或完整外部联接。 在 FROM子句中指定外联接时，可以由下列几组关键字中的一组指定：
2017-11-03 12:44:47
135
原创 1.1数组和链表：160. Intersection of Two Linked Lists(Leetcode)
Write a program tofind the node at which the intersection of two singly linked lists begins. Notes:If the two linked lists have no intersection at all, return null.The linked lists must reta
2017-11-02 15:08:35
117
原创 3.1 数学：172.Factorial Trailing Zeroes(Leetcode)
数学题，大致含义求N的阶乘结果后0的个数先贴代码：public int trailingZeroes(int n) { int factor = 5,countOfZeros = 0; while(n / factor > 0){ countOfZeros += n / factor; n /= 5;
2017-11-02 14:31:52
102
原创 1.1 数组和链表：169.Majority Element (Leetcode)
一道经典的面试题，找出数组中出现半数以上的元素（不包含半数）。先贴代码：public int majorityElement(int[] nums) { int result = 0,count = 0; for(int i = 0;i < nums.length;i ++){ if(count == 0){
2017-11-02 13:47:25
126
原创 1.4 字符串：168. Excel Sheet Column Title(Leetcode)
1.4 字符串题目要求：按EXCEL的序A~Z，AA~ZZ,...将给定正整数转化为此序列i.e: 1 ..... A,2.....B,26......Z,27.......AA.public String convertToTitle(int n) { String ret = ""; while(n > 0)
2017-11-02 10:46:18
193
原创 关于LINUX系统下部署javaweb项目失败报错404的问题
本人第一次写博文，主要是因为一个小问题让我浪费了一下午的时间。今天跟着视频学linux基础，最后在linux下部署web项目出现了问题，服务器报404错误，然后就一点一点开始百度找问题。然后发现因为视频少了一节课，导致jdk没有下载并配置。。。。但是在我配置完环境变量以后还是不行，然后就开始无尽的百度，有的说是访问权限问题，有的说是配置文件问题。。。然后我学着网上大神所说的打开了日
2017-08-27 19:27:59
8180
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2017-09-01
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