ACMSolver :: Art of Programming Contest, Tips and Tricks for C, C++, Java

• UVa Online Judge , over 2700 problems, C/ C++/ Pascal/ Java supported.
• Infoarena, over 1100 problems, C/ C++/ Pascal supported, over 15000 users. Only Romanian language.
• .Campion , over 900 problems, C/ C++/ Pascal supported. Only Romanian language.
• Caribbean Online Judge , C/ C++/ Pascal/ Java/ Python/ C# supported.
• Fuzhou University Online Judge, over 800 problems. Popular among the Chinese.^{[citation needed]}
• Harbin Institute of Technology Online Judge, over 1800 problems. Popular among Chinese people.^{[citation needed]}
• Lviv National University Online Judge, over 100 hard ACM-type problems. Only Ukrainian language.
• Moscow Problem Archive with Online Judge, supports C/C++/Java/Free Pascal/Perl/Python/Haskell/Kylix/Lua/OCaml/Ruby/Scheme.
• Peking University Online Judge, over 2800 problems including more than 200 original problems, supports C/C++/Pascal/Java/Fortran.
• Saratov State University Problem Archive with Online Judge, over 300 problems
• Tianjin University Online Judge, over 2000 problems, supports C/C++/Pascal/Java, virtual contests supported.
• Teddy Online Judge, includes problems in Spanish, supports C/C++/Python/Java/Perl.
• USACO|USA Computing Olympiad Training Site, hundreds of problems with complementary tutorials for incrementally expanding competitive programming skills; supports C, C++, Pascal and Java programming languages; targeted to pre-college students.
• Valladolid Problem Archive with Online Judge, about 2500 problems, supports C, C++, Pascal and Java programming languages
• Zhejiang University Online Judge, over 2400 problems, supports C, C++, Pascal and Java.
• Timus Online Judge, The Timus Online Judge is the largest Russian archive of problems from different programming contests. Accepts solutions in C/C++, Java, Pascal and C#.
• z-training , over 700 problems, C/ C++/ Pascal/ Java/ Python and 8 other languages supported. Provides PHP APIs for building custom online judges.
• Shenyang Institute of Engineering Online Judge, The SIE Online Judge contains over 200 problems for beginners, Chinese and English.
• Open Computer Science Community and Online Judge, Open CS has a permanently-growing problemset, that users can also contribute to. It also has a collection of computer science-related articles.

Some of the online judges designed for programming course are:

• Moodle Online Judge Plugin, an assignment type for Moodle, which can automatically grade C/C++ assignments.
• HUSTOJ, HUST Online Judge,C/C++/Pascal/Java/Ruby/Bash/Python supported, an open source OJ system using GPL2.0 license, which support LiveCD mode and FPS format.
• FPS, Free Problem Set, an open source problemset exchange format based on XML, which providing more than 400 free problems in FPS format.

A new online judge is going to start from Bangladesh which is now in test purpose open. This site is developed and owned by Jan-e-Alam, Graduate from DU and he is also an employee of Google. The site, temporarily used for AIUB and DU students practice is better than most of the sites available. You can also solve problem there.

Website: http://180.211.224.73/lightoj/login_main.php

For getting username/pass, mail to jan876_du@yahoo.com with your identity.

(News source: http://groups.yahoo.com/group/cuetcoders/)

A nice attempt to improve problem solving skills: http://www.questtosolve.com/

“(…)In the spirit of Steven Halim’s World of Seven: Methods to Solve website, that posted the solutions to hundreds of problems for the University of Valladolid (UVa) Online Judge website, we have decided to not only tackle UVa problems in preparation of ACM ICPC competition, but also to post the answers that we find for each problem in the hope that our repository of solutions will be as great an informational resource to programmers everywhere as Steven’s was.

Who are we? Two students majoring in Computing Science from Simon Fraser University in British Columbia, Canada.(…)”

The system’s development began in 2006 under the Xtreme Initiative. Then arose the opportunity to become in the COJ (sponsored by the Caribbean Community of the ACM-ICPC) and others people was joined to the small but inspired development team. Since June 2010 the COJ is available on the Internet.

Main goals of the COJ

To provide a space where people of the world can:

- exchange experiences and knowledge,

- test, improve and share theirs problem-solving and programming skills,

- training for programming contests (the ACM-ICPC, the IOI, etc.).

http://coj.uci.cu/OnlineJudge/