Technical Issues on Holding Practice Contests

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Technical Issues on Holding Practice Contests

• Yusuke Izumi
• Tokyo Institute of Technology
• Japanese Alumni Group

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Contents

• How we organize problem sets
• How we accept remote participants

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How Many Problems Needed?

• Practice for Preliminaries
• 6 problems
• Practice for Regional Contests
• 9 problems
• Summer/Winter Camps
• roughly 20 problems in total for 1 full set plus
  12 extra sets

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Means of Collaboration

• We cannot have on-site meetings so many times.
• We use network tools for discussions.
• PukiWiki
• mainly for technical topics
• fml (mailing lists)
• mainly for non-technical topics
• MSN Messenger
• for real-time discussions

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Typical Schedule
6 weeks
1st meeting

• rough time schedule
• of problems
• which kinds of problems to be presented

3 weeks
2nd meeting

• fix the problems

1 week
3rd meeting

• complete remaining tasks

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Working Page on Wiki (1 of 2)
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Working Page on Wiki (2 of 2)
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Our Policies Guidelines (1 of 2)

• Problems
• Various difficulty levels
• A wide range of categories
• Algorithmic and implementational
• Solutions
• At least two members for each problem write
  solution programs.

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Our Policies Guidelines (2 of 2)

• Data sets
• Typical cases
• Simple cases
• Boundary cases
• Special cases
• Random cases
• Validators
• Do not avoid creating validators.

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Problem Set of PC for RC06
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Picked-up Problems (1 of 2)
S

• Given a , b ? N, minimize Sk i ( ki 1 - ki
  ) 2 subject to k ? k i ? sort (? a1 , a2 , b1
  , b2 ?) such that a a1a2 , b b1b2 and ai , bi
  ? N.
• Example
• a 33 3 ? 11 , b 40 5 ? 8 ? k ? 3 , 5 ,
  8 , 11 ?
• Sk ( 5 - 3 ) 2 ( 8 - 5 ) 2 ( 11 - 8 ) 2 22

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Picked-up Problems (2 of 2)

• Find the longest palindrome among subse-quences
  of a given string.
• Find the shortest route that passes across or
  touches all line segments in a given order.

YMAOKDOAMIMHAADAMMA
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Contents

• How we organize problem sets
• How we accept remote participants

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PC2 over the Internet

• PC2 uses Java RMI.
• Connectivity to arbitrary ports required between
  servers and clients.
• VPN is maybe the only solution.

Server
Internet
Router
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PC2 over PPTP

• Advantage
• No extra software required for Windows.
• Disadvantage
• Some routers prevent connection for the lack of
  functionality or by the filter.
• Alternatives
• Other VPN technologies (e.g. OpenVPN)
• Other means of submissions

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CGI Submission System
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CGI Submission System

• Components
• File uploading tool
• Chat tool
• Specialized PC2 team client
• Advantage
• Requires only a Web browser.
• Disadvantage
• Interface differs from PC2.

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Entire System
Web Server
Web Client
CGI
Special Client
Judge
Remote Teams(CGI)
Online Balloons
PC2 Board
PC2 Judge
PC2 Team
PC2 Team
PPTP Server
PC2 Server
Local Teams
Remote Teams(VPN)
Contest Server
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Online Balloons
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Contest Resource Center
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Concluding Remarks

• We work for problem sets with on-line
  communication tools.
• We allow remote participation via VPN or the CGI
  system.
• Our method is not the only way.
• Any suggestion appreciated.