A. Sagheer and Crossroads time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Sagheer is walking in the street when he comes to an intersection of two roads. Each road can be represented as two…

Q&A参考连接 Problem:IOError: [Errno 2] No such file or directory. os.path.exists() 如果目录不存在,会返回一个0值. 所以,如果你如下使用该函数,会得到 Problem 中描述的错误,而且错误会定位在其他地方: import os try: os.path.exists("E:/Contact") #Check if dir exist except: os.mkdir("E:/Contact&…

B. Sagheer, the Hausmeister time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Some people leave the lights at their workplaces on when they leave that is a waste of resources. As a hausmeiste…

C. Sagheer and Nubian Market time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output On his trip to Luxor and Aswan, Sagheer went to a Nubian market to buy some souvenirs for his friends and relat…

hadoop集群性能低下的常见原因 (一)硬件环境 1.CPU/内存不足,或未充分利用 2.网络原因 3.磁盘原因 (二)map任务原因 1.输入文件中小文件过多,导致多次启动和停止JVM进程.可以设置JVM重用. 2.数据倾斜:大文件且不可分割,导致处理这些文件的map需要很长时间. 3.数据本地化效果差. (三)reduce任务的原因 1.reduce任务数量过大或过小 2.数据倾斜:一部分key的记录数量太大,导致某些reduce执行过慢 3.缓慢的shuffle和排序 (四)hadoop…

Self Numbers Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 22101   Accepted: 12429 Description In 1949 the Indian mathematician D.R. Kaprekar discovered a class of numbers called self-numbers. For any positive integer n, define d(n) to…

Debian6添加了insserv用来代替update-rc.d.update-rc.d 就不多做介绍. Debian6里边要添加一个自动启动的服务需要先将启动脚本放在/etc/init.d,然后使用insserv来启用这个服务. 例如服务名称为 myserver,则脚本为/etc/init.d/myserver. 然后使用 insserv myserver可以将myserver设为自动启动: </pre><pre name="code" class="py…

UIView 视图类,视图都是UIView或者UIView子类 UIWindow 窗口类,用于展示视图,视图一定要添加window才能显示 注意:一般来说,一个应用只有一个window 创建一个UIWindow对象 UIScreen 屏幕类 [UIScreen mainScreen]主屏幕 [[UIScreen mainScreen]bounds]获得主屏幕大小 如: 1.创建工程 2.把ARC改为MRC 3.window的属性由string改为retain 4.重写dealloc方法,对_wi…

1.Foundation框架中提供了很多的集合类如:NSArray,NSMutableArray,NSSet,NSMutableSet,NSDictionary,NSMutableDictionary但是这些类只能存放OC对象类型的数据 2.如果要存放基本数据类型,必须先将基本暑假类型包装成对象类型然后再用集合类进行存储,OC中提供的包装类是NSNumber,NSValue.其中NSNumber继承于NSValue. 3.NSNumber主要针对于基本数据类型的包装,NSValue主要针对结构体…

Free Kick Time Limit: 2 Seconds      Memory Limit: 65536 KB In a soccer game, a direct free kick is also awarded to the opposing team if a player commits any of the offences. A direct free kick in an immediate distance is a nightmare of the goalie. I…