1. Tips on How To Organize your Own Practice Contest University of Tokyo Shunsuke SOEDA 21 st November 2004

2. Todays Talk WHAT, WHO, WHY, WHEN, HOW WHAT is a practice contest WHY you should organize one WHO would like to organize one Some tips on HOW to organize one

3. WHAT What is a practice contest? To have a practice just like a real contest Gather the teams you know Inter colligate Ask your friends to do judges Prepare problems Set up PC 2

4. WHY Why you should hold a practice contest To switch on the contestants Contestants feel their rivals Get used to the PC 2 system Give them confidence

5. WHO Who wants to hold a practice contest Intermediate to advanced contestants Beginners tend to lose confidence

6. HOW Some tips on preparing a practice contest Preparing the problems For remote attendees

7. HOW Some tips on preparing a practice contest Preparing the problems For remote attendees

8. Preparing the problems Most time consuming part Selected nine problems Six from past problems Three original problems

9. Selecting Past Problems Six problems out of ~120 candidates Eight ex-contestants, ~2 contests each Avoided problems on UVA online judge Avoided problems from past regional contest held in Japan Problems from eastern Europe Well thought, strict answer

10. Original Problems Three original problems Some new problems to let the contestants think a bit Quite enjoyable for the problem makers as well!

11. HOW Some tips on preparing a practice contest Preparing the problems For remote attendees

12. Remote Attendance It is essential to have strong teams in your contest Some teams willing to attend from remote Teams online

13. VPN + PC 2 SERVER (SITE2) U-TOKYO (HONGO) U-TOKYO (KOMABA) REMOTE SERVER (SITE1) VPN ROUTER TEAM JUDGE ADMIN

14. Problems PC 2 uses RMI PC 2 client programs send their original IPs, instead of ones given for the VPN connection The server cannot connect back to the client

15. Problems SERVER (SITE2) U-TOKYO (HONGO) U-TOKYO (KOMABA) REMOTE SERVER (SITE1) VPN ROUTER TEAM JUDGE ADMIN 192.168.1.1 192.168.0.56 192.168.7.13 192.168.0.55 192.168.0.4

16. Problems SERVER (SITE2) U-TOKYO (HONGO) U-TOKYO (KOMABA) REMOTE SERVER (SITE1) VPN ROUTER TEAM JUDGE ADMIN I am 192.168.11.1 I am 192.168.7.13

17. Problems SERVER (SITE2) U-TOKYO (HONGO) U-TOKYO (KOMABA) REMOTE SERVER (SITE1) VPN ROUTER TEAM JUDGE ADMIN OK, 192.168.11.1? 192.168.7.13?

18. Problems: THE PACKETS ARE LOST! SERVER (SITE2) U-TOKYO (HONGO) U-TOKYO (KOMABA) REMOTE SERVER (SITE1) VPN ROUTER TEAM JUDGE ADMIN OK, 192.168.11.1? 192.168.7.13?

19. Solution For the server Tell to router to send back packets to the VPN modify the routing table For the teams Use java.rmi.server.hostname e.g. java -Djava.security.policy=all.policy -Djava.rmi.server.hostname=192.168.0.65 pc2.client.Client

20. Solved SERVER (SITE2) U-TOKYO (HONGO) U-TOKYO (KOMABA) REMOTE SERVER (SITE1) VPN ROUTER TEAM JUDGE ADMIN 192.168.11.1 Is on VPN I am 192.168.0.55

21. Balloons! Something you just cant do away with Affording Helium might be a bit too much

22. Balloons: Solution Hang them down

23. Balloons: Solution qoo_ solved one problem

24. Balloons: Solution The same scenery

25. Results Yet to come

26. Acknowledgement IZUMI, Yusuke KASAHARA, Masahiro MATSUZAKI, Kiminori MIKURUBE, Dai SHIGETOMI, Rie

27. Thank You