03 2016 档案
摘要：1、在没有IDE自动补齐的情况下，怎样得到数组的长度？怎样得到字符串的长度？ 为什么数组有length属性而String只有length()方法呢？ 2、为什么Arrays有length属性？ 首先，数组是一个对象容器，保存的是一系列单一类型的值；然后数组被创建，但是长度不能被改变；数组的长度可以当
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摘要：1、来看一段有趣但又让人困惑的代码片段 打印结果："ab" 2、这段代码真正做了什么呢？来解释一下这个过程 首先，当字符串"ab"被创建时，Java分配内存来存储这个字符串常量；然后，这个字符串常量被赋值给了变量x，x实际上保存的是这个字符串对象的引用地址(内存中的地址)；x变量保存了字符串对象的引
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摘要：Implement atoi to convert a string to an integer. Hint: Carefully consider all possible input cases. If you want a challenge, please do not see below
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摘要：Reverse digits of an integer. If the integer's last digit is 0, what should the output be? ie, cases such as 10, 100.Did you notice that the reversed
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摘要：Given a string S, find the longest palindromic substring in S. You may assume that the maximum length of S is 1000, and there exists one unique longes
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摘要：There are two sorted arrays nums1 and nums2 of size m and n respectively. Find the median of the two sorted arrays. The overall run time complexity sh
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摘要：Given a string, find the length of the longest substring without repeating characters. For example, the longest substring without repeating letters fo
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摘要：You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single
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摘要：1、在Java中，创建一个字符串有两种方式 String x = "abc";String y = new String("abc"); 这两种方式有什么区别呢？ 2、双引号("")和构造器 第一个案例： String a = "abcd";String b = "abcd";System.out.
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摘要：1、在Java中，String类是不可变类，一个不可变类是一个简单的类，并且这个的实例也不能被修改， 这个类的实例创建的时候初始化所有的信息，并且这些信息不能够被修改 2、字符串常量池 字符串常量池是方法区中一块特殊的存储区域，当创建一个字符串常量的时候，判断该字符串字在符串字符串常量池中是否已经存
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摘要：1、substring()方法做了什么？ substring(beginIndex,endIndex)方法返回一个从beginIndex到endIndex-1的字符串 String x = "abcdef"; x = x.substring(1,3); System.out.println(x);
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摘要：声明一个字符串引用变量： String s = "abcd"; s是一个引用变量，指向 堆内存中的字符串常量 "abcd" 再声明一个字符串引用变量： String s2 = s; 把s变量赋值给s2，那么 s 和 s2 两个引用变量同时指向堆内存中的字符串常量 "abcd" 改变字符串： s =
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摘要：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 the Users tabl
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摘要：The Employee table holds all employees. Every employee has an Id, and there is also a column for the department Id. The Department table holds all dep
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摘要：Write a SQL query to find all numbers that appear at least three times consecutively. For example, given the above Logs table, 1 is the only number th
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摘要：Write a SQL query to rank scores. If there is a tie between two scores, both should have the same ranking. Note that after a tie, the next ranking num
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摘要：Write a SQL query to get the nth highest salary from the Employee table. For example, given the above Employee table, the nth highest salary where n =
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摘要：The Employee table holds all employees. Every employee has an Id, a salary, and there is also a column for the department Id. The Department table hol
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摘要：Write a SQL query to delete all duplicate email entries in a table named Person, keeping only unique emails based on its smallest Id. For example, aft
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摘要：Given a Weather table, write a SQL query to find all dates' Ids with higher temperature compared to its previous (yesterday's) dates. For example, ret
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摘要：Table: Person Table: Address Write a SQL query for a report that provides the following information for each person in the Person table, regardless if
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摘要：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
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摘要：Write a SQL query to find all duplicate emails in a table named Person. For example, your query should return the following for the above table: CREAT
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摘要：The Employee table holds all employees including their managers. Every employee has an Id, and there is also a column for the manager Id. Given the Em
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摘要：我在上一篇博客中说明了在爬取数据的时候，把数据写入到文件的乱码问题 在这一篇里面我做一个总结： 1、首先应该看一个案例 我把数据写在.py文件中： #coding:utf-8 s = 'hehe测试中文字符'ss = u'hehe测试中文字符'uu = s.decode('utf-8') print
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摘要：之前在写的时候没有遇到过这个问题，用惯了eclipse之后突然用Notepad++就出现乱码了 我在编写的时候 指定Noepad++的编码是 UTF-8编码，然后进入命令行，编译的时候就出现了乱码 然后我用UTF-8无BOM编码，虽然能通过编译，但是输出的时候，还是出现了乱码 搜了一下，发现问题在于
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摘要：一、读取返回的页面数据 在浏览器打开的时候查看源代码，如果在头部信息中指定了UTF-8 那么再python代码中读取页面信息的时候，就需要指定读取的编码方式： response.read().decode('utf-8') 二、把中文数据写入到文件的时候 python默认的是按照ACSII的编码往外
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摘要：这里用知乎(www.zhihu.com)来测试的python的模拟登陆操作 首先用FIreFox和Fiddler来拦截所有对知乎的请求，包括进入登陆的页面的url(www.zhihu.com/signin)和登陆的url(www.zhihu.com/login/phone_num) 查看页面的源代码
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