web.xml报错
The content of element type "web-app" must match "(icon?,display-
name?,description?,distributable?,context-param*,filter*,filter-mapping*,listener*,servlet*,s
JUnit4：Test文档中的解释：
The Test annotation supports two optional parameters.
The first, expected, declares that a test method should throw an exception.
If it doesn't throw an exception or if it
借鉴网上的思路，用java实现：
public class NoIfWhile {
/**
* @param args
*
* find x=1+2+3+....n
*/
public static void main(String[] args) {
int n=10;
int re=find(n);
System.o
在Linux中执行.sh脚本，异常/bin/sh^M: bad interpreter: No such file or directory。
分析：这是不同系统编码格式引起的：在windows系统中编辑的.sh文件可能有不可见字符，所以在Linux系统下执行会报以上异常信息。
解决：
1）在windows下转换：
利用一些编辑器如UltraEdit或EditPlus等工具
Binary search tree works well for a wide variety of applications, but they have poor worst-case performance. Now we introduce a type of binary search tree where costs are guaranteed to be loga
4、进行pycharm的配置和主题修改