Practice Tasks

Task list

There are 3 practice tasks:

Notes: There are updates in the limits in tasks Hottest and Valley.

How to practice

Set up the contest environment as described in here. You should use the RunC environment for testing (read the overview on how to use RunC and see tutorial from the IOI 2010 website). For each practice task, you can download its prototype that works with the RunC tools from the implementation details section in the task.

On-line practice session

The on-line practice server is up at: https://practice.ioi2011.or.th:8443/.

The username and password will be mailed to the delagation leaders and deputy leaders, after the teams have registered. As the mailing will be done daily (and semi-manually), you may receive the usernames and passwords a day or two after you have registered. If your team has already registered but you did not get the passwords, please send e-mail to hsc@ioi2011.or.th.

Note that the goal of the on-line practice session is to get you familiar with the tools and the environment. However, the grading machine for the on-line practice is not the same as the ones to be used during the IOI. Therefore, in terms of performance, you should expect the differences with the real environment.

Runc and submission scripts for on-line practice

Notes: There are updates in the submit_task script.

If you would like to use command line submission submit and to try the TEST interface, you should follow the instructions below to install the submission scripts on Ubuntu 10.10. It also comes with the runc environment introduced in last year IOI.

The submit and submit_test scripts use java, so you should install java with the following command:

  sudo apt-get install openjdk-6-jre-headless

If you want the environment that integrates with gedit, please download RunC-full.sh. If you only want the command-line version, please download RunC-lite.sh.

Then at the terminal, issue the following commands (replacing RunC-full.sh with RunC-lite.sh as appropriate):

  sudo apt-get install sharutils
  sh RunC-full.sh
  sudo ln -s ~/.RunC/runc /usr/bin
  sudo ln -s ~/.RunC/submit /usr/bin
  sudo ln -s ~/.RunC/submit_test /usr/bin

If you have already installed runc, you may get an error like

ln: creating symbolic link '/usr/bin/runc': File exists,

but this is OK.

Configure username and password

If you use scripts in command line, the scripts will ask for your username and password every time you submit a solution or a test request.

During the competition, your username and password will be pre-configured into the submit and submit_test scripts. This is more convenience and is required if you would like to submit directly from gedit.

To do so, during the on-line practice, you can add the username and password in files submit or submit_test in directory ~/.RunC, as shown below.

  #!/bin/sh
  USERNAME=        # put your username here, e.g., USERNAME=tha9
  PASSWORD=        # put your password here, e.g., PASSWORD=nopass

Solution submission

You can either call submit from the command line by typing one of

  submit grader.c
  submit grader.cpp
  submit grader.pas

from the directory containing your solution. All files with the same extension will be zipped together and submitted to the server. Since the script uses the directory name as the task name, you should call this from an appropriate directory, e.g., to submit solutions to task hottest, you should call submit in directory hottest.

Usually, you call submit from the directory containing the prototype solutions where you call runc for testing.

Also, while editing the solution files in gedit, you may press Ctrl-J to submit the solution. In this case, please make sure that you have configure your username and password in the submit script.

TEST interface

You can test your solutions with your own the input file in the server. To do so, you can call

  submit_test [your-main-program] [your-input-file]

For example, if you write in Pascal, your main program is grader.pas, and your input is input.in, you should call

  submit_test grader.pas input.in

If your main program is test.c, and your input is test.in, you should call

  submit_test test.c test.in

The script will submit all source files with the same extension as the main program and the input.

You can view the execution statistics and the first 100 characters of the first 100 lines of the output from the task TEST interface.

Comments and questions

If you have any problems or comments with contest environment, please send e-mail to hsc@ioi2011.or.th.