Yearly Archives: 2017

Blackgate Penitentiary

 in Informatics Olympiads / xtreme  tagged batbear / batman / Blackgate Penitentiary / Informatics / joker / Olympiad / vangelis by

Vangelis the Batbear trapped all the members of Joker’s Streetgang in a basement.
Your job as a police officer is to transport all gang members to Blackgate Penitentiary.

To facilitate the transport, you should form a row such that the heights of the gang members are in non-decreasing order. For each gang member you should find the min and the max position where they can be in a valid sorted row and produce a roster with this information.

Input data

Input will start with a line that contains only one integer M, the number of crew members that were arrested. On each of the following M lines there will be a single word N and an integer H separated by a space character, where N is the name and H is the height of the crew member.

Output data

On the output, there will be G lines. Each line will contain in alphabetical order and space separated the names of the crew members that have the same height, followed by the min and the max position where any member of the specific group can be placed.

Limitations and notes

1 ≤ M ≤ 1000
1 ≤ length(N) ≤ 10
120 ≤ H ≤ 250

Names are only composed of characters of the Latin alphabet.

Batman and the Bubbles challenge

 in Informatics Olympiads / xtreme  tagged batbear / batman / bubbles / Informatics / joker / Olympiad / vangelis by

Good evening master Wayne.

Joker and his gang attended Black Hat USA 2017 where they learned of a new way on how to damage our city!
Specifically, tomorrow night they will try to damage the water pumps of Gotham using bubbles!
The bubbles cause corrosion to the pumps and in a few hours they will damage them with catastrophic results!
To dash Joker’s plan, besides stopping him, you need to make sure that the city network does not contain loops.
If Joker manages to inject bubbles to the network and they enter a loop, they will still cause damage to that area even though you would have already arrested Joker and his gang.

Given the map of the water distribution system, you need to make sure that the map does not contain loops.

Input data

On the first line there will be an integer T, the number of test cases to follow.
For each test case, there will be 2 input lines:

  1. On the first line of the test case, there will be 2 integers V and E, where V is the number of vertices and E is the number of edges.
  2. On the second line, there will be E pairs of integers separated by a space character. Each pair shows a two way connection between vector A with vector B.

Output data

For each test case you will have to write one line that contains an integer, in the case where there is a loop you will write the number 1 or else you will write the number 0.

Limitations and notes

1 ≤ T ≤ 1000
1 ≤ V ≤ 1000
1 ≤ E ≤ 10000
0 ≤ A,B ≤ V-1

Vangelis the bear is Batman! (or Batbear to be more precise).

Vangelis the bear is Batman! (or Batbear to be more precise).

Reading material

Supplementary material

  • Random test case generator – [download id=”3801″]

Create a graph out of an XML file

 in Applications  tagged graph editor / xml / yEd by

To create a graph out of an XML file, we used the yEd graph editor.
yEd is a desktop application that can be used to generate diagrams. It is free of charge (not FOSS) and runs on all major platforms: Windows, Unix/Linux, and Mac OS X.

For the following demo we used the latest release for GNU/Linux that was available at the time (yEd-3.17.1).

Usage Example

  1. Download yEd
  2. Extract it
  3. Navigate into the generated folder (e.g. if you used the attached version then the folder will be yed-3.17.1)
  4. Start the application using a JRE. In our case the command to start it was: java -jar yed.jar
  5. Click on the Open option (or go to File > Open... )
  6. Navigate to the XML file that you want to graph and click Open
  7. In the pop-up window for the drop-down named XSL File for then select the option XML-Tree and click Ok
  8. By now you should have your graph available to view/edit/export

CentOS 6: install / start and stop / enable and disable ssh server

 in GNU/Linux  tagged chkconfig / fedora / openssh-server / server / ssh / system by

Install

To install the openssh-server, you need to install the openssh-server package:

sudo yum install -y openssh-server;

Start

To start the sshd daemon (openssh-server) in the current session:

sudo service sshd start;

Stop

To stop the active (if any) sshd daemon in the current session:

sudo service sshd stop;

Enable

To configure the sshd daemon to start automatically at boot time:

sudo chkconfig sshd --add;
sudo chkconfig sshd on --level 2,3,4,5;

Disable

To configure the sshd daemon to stop automatic initialization at boot time:

sudo chkconfig sshd off;
sudo chkconfig sshd --del;