小编kof*_*rts的帖子

bigO中以下算法的运行时间是多少？

for(int i=1;i<=n;i++){
    for(int j=i;j<=n;j++){
        for(int k=j; k<=n;k++){
            for(int l=k; l<=n;l++){

                ...

            }
        }
    }
}

我正在使用腻子从我的桌面在远程 linux 机器上使用 ssh。我想将本地 Windows 计算机桌面上的 txt 文件复制到远程 linux 目录。当我使用 ssh 登录到远程机器时，如何使用 shell 做到这一点？谢谢您的帮助！

function handleCheckboxClick(event){

    if(document.getElementById(event.target.id).checked){

      document.getElementById(event.target.id.concat("_visible")).setAttribute("checked", "true");
      console.log(document.getElementById(event.target.id.concat("_visible")));		   				   		
  }
}

var requiredCheckboxes = document.getElementsByClassName("checkbox_required");

for (var i = 0, max = requiredCheckboxes.length; i < max; i++){
   requiredCheckboxes[i].addEventListener('click', handleCheckboxClick);		    
}

<table>    			
	<tr>
		<th>
			Property
		</th>
		<th>
			Visible
		</th>
		<th>
			Required
		</th>
	</tr>
	
	<tr>
		<td>
			Email  
		</td>
		<td>
			<input type="hidden" name="_email_visible" /><input type="checkbox" name="email_visible" id="donation_email_visible"  />
		</td>										
		<td>
			<input type="hidden" name="_email" /><input type="checkbox" name="email" class="checkbox_required" id="donation_email"  />
		</td>
	</tr>
	
</table>

首先,单击电子邮件所需的复选框.正如预期的那样,还会检查可见框.现在,勾选可见框并单击对应于电子邮件的必填复选框,该复选框将检查电子邮件所需的框.现在再次单击所需的电子邮件复选框,将不会选中可见复选框.所以,这就是我的困境所在.在第二次点击需要时,为什么不检查可见框？我感谢您的帮助!谢谢!

我已经在cloud9的端口8081上运行elasticsearch。

/workspace/elasticsearch-6.1.1/bin $ ./elasticsearch -E http.port=8081

然后我在 gemfile 中添加“searchkick”gem，然后捆绑安装

然后我在模型中添加 searchkick 作为

class Book < ActiveRecord::Base
    searchkick
end

然后我运行命令

Book.reindex

我收到以下错误

2.3.4 :001 > Book.reindex
Faraday::ConnectionFailed: Failed to open TCP connection to localhost:9200 (Connection refused - connect(2) for "localhost" port 9200)
        from /usr/local/rvm/rubies/ruby-2.3.4/lib/ruby/2.3.0/net/http.rb:882:in `rescue in block in connect'
        from /usr/local/rvm/rubies/ruby-2.3.4/lib/ruby/2.3.0/net/http.rb:879:in `block in connect'
        from /usr/local/rvm/rubies/ruby-2.3.4/lib/ruby/2.3.0/timeout.rb:91:in `block in timeout'
        from /usr/local/rvm/rubies/ruby-2.3.4/lib/ruby/2.3.0/timeout.rb:101:in `timeout'
        from /usr/local/rvm/rubies/ruby-2.3.4/lib/ruby/2.3.0/net/http.rb:878:in `connect'
        from /usr/local/rvm/rubies/ruby-2.3.4/lib/ruby/2.3.0/net/http.rb:863:in `do_start'
        from /usr/local/rvm/rubies/ruby-2.3.4/lib/ruby/2.3.0/net/http.rb:852:in `start'

这是有道理的，因为它假设弹性搜索服务器在默认的 9200 上运行，但我在 8081 上运行它。我如何告诉 searchkick gem 连接到 8081 端口而不是 …

我想打开浏览器，单击某些字段，然后发送击键。

以下代码在屏幕上的任何位置都单击。

win32api.SetCursorPos((x,y))
win32api.mouse_event(win32con.MOUSEEVENTF_LEFTDOWN,x,y,0,0)
win32api.mouse_event(win32con.MOUSEEVENTF_LEFTUP,x,y,0,0)

现在，我想向该活动应用程序发送击键。我怎样才能做到这一点？

我想用capybara用rspec.

的Gemfile

group :test do
  gem 'capybara'
end

根据文档,我需要添加require 'capybara/rspec'到rails_helper.rb,我做了:

require 'spec_helper'
ENV['RAILS_ENV'] ||= 'test'
require File.expand_path('../../config/environment', __FILE__)

abort("The Rails environment is running in production mode!") if Rails.env.production?

require 'rspec/rails'
require 'capybara/rspec'

ActiveRecord::Migration.maintain_test_schema!

RSpec.configure do |config|
  config.fixture_path = "#{::Rails.root}/spec/fixtures"
  config.use_transactional_fixtures = true
  config.infer_spec_type_from_file_location!    
  config.filter_rails_from_backtrace!
end

现在,当我跑bundle exec rspec.我得到:

Failure/Error: visit('/')

     NoMethodError:
       undefined method `visit' for #<RSpec::ExampleGroups::HomeFooters:0x000000035cc4b8>

测试如下:

require 'rails_helper'

RSpec.describe "HomeFooters", type: :request do
  it "show proper links in footer" …