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

Tips on How To Organize your Own Practice Contest

University of Tokyo

Shunsuke SOEDA

21st November 2004

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Today’s 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

SERVER(SITE2)

U-TOKYO

(HONGO)

U-TOKYO

(KOMABA)

REMOTE

SERVER(SITE1)

VPN ROUTER

TEAM

TEAM

TEAM

TEAM

JUDGE

ADMIN

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Problems

PC2 uses RMI PC2 client programs send their original

IP’s, instead of ones given for the VPN connection

The server cannot connect back to the client

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Problems

SERVER(SITE2)

U-TOKYO

(HONGO)

U-TOKYO

(KOMABA)

REMOTE

SERVER(SITE1)

VPN ROUTER

TEAM

TEAM

TEAM

TEAM

JUDGE

ADMIN

192.168.1.1

192.168.0.56

192.168.7.13

192.168.0.55192.168.0.4

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Problems

SERVER(SITE2)

U-TOKYO

(HONGO)

U-TOKYO

(KOMABA)

REMOTE

SERVER(SITE1)

VPN ROUTER

TEAM

TEAM

TEAM

TEAM

JUDGE

ADMIN

I am 192.168.11.1

I am 192.168.7.13

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Problems

SERVER(SITE2)

U-TOKYO

(HONGO)

U-TOKYO

(KOMABA)

REMOTE

SERVER(SITE1)

VPN ROUTER

TEAM

TEAM

TEAM

TEAM

JUDGE

ADMIN

OK, 192.168.11.1?192.168.7.13?

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Problems: THE PACKETS ARE LOST!

SERVER(SITE2)

U-TOKYO

(HONGO)

U-TOKYO

(KOMABA)

REMOTE

SERVER(SITE1)

VPN ROUTER

TEAM

TEAM

TEAM

TEAM

JUDGE

ADMIN

OK, 192.168.11.1?192.168.7.13?

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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.policy=all.policy -Djava.rmi.server.hostname=192.168.0.65 pc2.client.Client

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Solved

SERVER(SITE2)

U-TOKYO

(HONGO)

U-TOKYO

(KOMABA)

REMOTE

SERVER(SITE1)

VPN ROUTER

TEAM

TEAM

TEAM

TEAM

JUDGE

ADMIN

192.168.11.1Is on VPN

I am 192.168.0.55

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Balloons!

Something you just can’t 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