Tips on How To Organize your Own Practice Contest

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

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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

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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 PC2

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WHY

• Why you should hold a practice contest
• To switch on the contestants
• Contestants feel their rivals
• Get used to the PC2 system
• Give them confidence

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WHO

• Who wants to hold a practice contest
• Intermediate to advanced contestants
• Beginners tend to lose confidence

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HOW

• Some tips on preparing a practice contest
• Preparing the problems
• For remote attendees

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HOW

• Some tips on preparing a practice contest
• Preparing the problems
• For remote attendees

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Preparing the problems

• Most time consuming part
• Selected nine problems
• Six from past problems
• Three original problems

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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

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Original Problems

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

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HOW

• Some tips on preparing a practice contest
• Preparing the problems
• For remote attendees

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Remote Attendance

• It is essential to have strong teams in your
  contest
• Some teams willing to attend from remote
• Teams online

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VPN PC2
U-TOKYO (HONGO)
U-TOKYO (KOMABA)
REMOTE
VPN ROUTER
SERVER (SITE2)
SERVER (SITE1)
TEAM
ADMIN
TEAM
TEAM
JUDGE
TEAM
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Problems

• PC2 uses RMI
• PC2 client programs send their original IPs,
  instead of ones given for the VPN connection
• The server cannot connect back to the client

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Problems
U-TOKYO (HONGO)
U-TOKYO (KOMABA)
REMOTE
VPN ROUTER
192.168.0.55
192.168.0.4
192.168.0.56
SERVER (SITE2)
SERVER (SITE1)
TEAM
192.168.7.13
192.168.1.1
ADMIN
TEAM
TEAM
JUDGE
TEAM
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Problems
U-TOKYO (HONGO)
U-TOKYO (KOMABA)
REMOTE
I am 192.168.7.13
I am 192.168.11.1
VPN ROUTER
SERVER (SITE2)
SERVER (SITE1)
TEAM
ADMIN
TEAM
TEAM
JUDGE
TEAM
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Problems
U-TOKYO (HONGO)
U-TOKYO (KOMABA)
REMOTE
OK, 192.168.11.1? 192.168.7.13?
VPN ROUTER
SERVER (SITE2)
SERVER (SITE1)
TEAM
ADMIN
TEAM
TEAM
JUDGE
TEAM
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Problems THE PACKETS ARE LOST!
U-TOKYO (HONGO)
U-TOKYO (KOMABA)
REMOTE
OK, 192.168.11.1? 192.168.7.13?
VPN ROUTER
SERVER (SITE2)
SERVER (SITE1)
TEAM
ADMIN
TEAM
TEAM
JUDGE
TEAM
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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.policyall.policy
  -Djava.rmi.server.hostname192.168.0.65
  pc2.client.Client

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

• Something you just cant do away with
• Affording Helium might be a bit too much

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Balloons Solution

• Hang them down

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Balloons Solution

• qoo_ solved one problem

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Balloons Solution

• The same scenery

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Results

• Yet to come

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Acknowledgement

• IZUMI, Yusuke
• KASAHARA, Masahiro
• MATSUZAKI, Kiminori
• MIKURUBE, Dai
• SHIGETOMI, Rie

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Thank You