昨天做了一道简单但很麻烦的题,我只能想到结构体,并用了STL的sort方法解决了它.不过从中有许多细节问题. 题目: Problem Description Lcy wanted to choose 50 ACMers from m players to join HDU-ACM team. He made n competitions , and now is your task to make the rankli…
1,设置路由默认控制器设置文件application/config/routes.php$route[default_controller] welcome;我们新建一个控制器文件application/controllers/article.php<?php class Article extends CI_Controller{public function index(){echo "这是一个Articl…
说明:为了安装Docker,当前虚拟机不满足要求,版本如下: [rootlocalhost116 ~]# uname -r
2.6.32-573.el6.x86_64
[rootlocalhost116 ~]# cat /etc/issue
Red Hat Enterprise Linux Server release 6.7 (Santiago)
Kernel \r on an …
就个人而言,我会使用CHR()来识别零值。 nul是ASCII 0, CHR()将返回您传入的数字的字符表示。SQL> with the_data as (2 select a || chr(0) || b as str from dual3 union all4 select a || c from dual5 )6 select dump(str)7 from the_data8 where …
在介绍GROUP BY 和 HAVING 子句前,我们必需先讲讲sql语言中一种特殊的函数:聚合函数,例如SUM, COUNT, MAX, AVG等。这些函数和其它函数的根本区别就是它们一般作用在多条记录上。 SELECT SUM(population) FROM bbc 这里的SUM作用在所有返回记…