[TopCoder]SRM 647 Div2 Travelling Salesman Easy

题目描述:

You are a traveling salesman. You have already heard a lot about how hard the problems of a traveling salesman can be. Luckily, the one you currently have seems easier.

There are M cities where you can sell products ...

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[LeetCode]Department Top Three Salaries

题目描述:

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 |
+----+-------+--------+--------------+
| 1  | Joe   | 70000  | 1            |
| 2  | Henry | 80000  | 2            |
| 3  | Sam   | 60000  | 2            |
| 4  | Max ...

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深入了解Alexa排名

什么是Alexa排名?

Alexa排名反映了一个网站的受欢迎程度。最受欢迎的网站的Alexa排名为1。如果Alexa的排名为100,000,则说明这个网站是全球第100,000受欢迎的网站。通常人们提到的Alexa排名指的是全球排名,此外Alexa还有各个国家的网站排名。

怎样获取某个特定网站的Alexa排名?

你可以安装浏览器扩展(官方工具栏 或者 Chrome , Firefox工具栏),然后当你浏览网站时就可以看到对应网站的Alexa排名了。

或者也可以直接访问http://www.alexa.com,在搜索框中键入网站域名进行查询。

Alexa排名是怎样计算的?

如前所述,许多用户安装了Alexa的浏览器工具栏或者扩展,它们会将用户访问网站的信息发送给alexa.com。你可能很惊讶,但有数百万的人在这样做。Alexa跟踪这些人最近3个月访问的网站数据,并据此对网站进行排名。

Alexa的创始人是谁?

Alexa最早由两个合伙人创办于1996年,命名为Alexa互联网公司。名字的灵感来自于著名的亚历山大图书馆(Library of Alexandria)。他们基于用户的数据开发了一个为用户提供网站浏览推荐的“接下来去哪”的工具栏 ...

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[LeetCode]Department Highest Salary

题目描述:

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 | DepartmentId |
+----+-------+--------+--------------+
| 1  | Joe   | 70000  | 1            |
| 2  | Henry | 80000  | 2            |
| 3  | Sam   | 60000  | 2 ...

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[LeetCode]Customers Who Never Order

题目描述:

Suppose that a website contains two tables, the Customers table and the Orders table. Write a SQL query to find all customers who never order anything.

Table: Customers.

+----+-------+
| Id | Name  |
+----+-------+
| 1  | Joe   |
| 2  | Henry |
| 3  | Sam   |
| 4  | Max   |
+----+-------+

Table ...

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