What about Codeforces?

 Codeforces is an online platform that provides algorithmic challenges and competitions for programmers of all levels. It was created in 2009 by a group of Russian programmers as a way to practice and improve their algorithmic skills. Since then, it has grown into a global community of programmers who compete and collaborate on coding challenges.

Codeforces hosts regular coding competitions, including weekly rounds and educational rounds. These competitions provide challenging algorithmic problems that cover a wide range of topics, including dynamic programming, graph algorithms, and number theory. Each problem has a time limit and requires the programmer to write a solution that meets the problem's requirements and passes all the test cases.

Codeforces competitions are divided into different divisions based on the difficulty of the problems. The divisions range from Div. 1, which includes the most difficult problems, to Div. 3, which includes the easiest problems. This allows programmers of different skill levels to compete against others who are at a similar level.

In addition to the regular competitions, Codeforces also hosts special events and contests, including the Codeforces Global Rounds and the Codeforces SnarkNews Competition. These events provide opportunities for programmers to compete against others from around the world and win prizes.

Codeforces also includes a virtual rating system that ranks programmers based on their performance in the competitions. The rating system takes into account the difficulty of the problems that the programmer has solved and the time it took to solve them. This provides an incentive for programmers to improve their algorithmic skills and compete in more challenging competitions.

Codeforces has a strong community of programmers who collaborate and share their solutions and techniques. The platform includes a discussion forum where users can ask for help with problems and share their solutions. This allows programmers to learn from others and improve their algorithmic skills.

Codeforces also includes a blog section where users can publish articles and tutorials on algorithmic topics. This provides a resource for programmers to learn new concepts and techniques and share their knowledge with others.

Overall, Codeforces is a great platform for programmers to practice and improve their algorithmic skills. With its challenging problems, supportive community, and virtual rating system, Codeforces provides an engaging and motivating environment for programmers of all levels.

Here are some additional details about Codeforces:

1. Codeforces problem archive: The Codeforces problem archive includes over 8000 algorithmic problems organized by topic and difficulty level. These problems cover a wide range of algorithms and data structures, making it a great resource for practicing and learning new techniques.

2. Codeforces rating system: The Codeforces rating system is based on a player's performance in the competitions. The rating is calculated based on the difficulty of the problems solved and the time taken to solve them. The rating system allows users to track their progress and compare themselves to other users.

3. Codeforces educational rounds: Codeforces educational rounds are designed to help users improve their algorithmic skills. These rounds include problems that cover a specific topic or technique, and they include explanations and tutorials to help users learn and practice.

4. Codeforces virtual contests: Codeforces virtual contests allow users to participate in a past competition as if it were happening in real-time. This allows users to practice and compete at their own pace and time.

5. Codeforces APIs: Codeforces provides APIs that allow users to access data about problems, competitions, and users. This allows users to build their own tools and applications that use Codeforces data.

6. Codeforces extensions and plugins: Codeforces has many extensions and plugins available for popular code editors like Visual Studio Code, IntelliJ IDEA, and Sublime Text. These plugins provide shortcuts and features that make it easier to participate in competitions and practice problems.

7. Codeforces community: The Codeforces community includes a discussion forum, blogs, and social media accounts. The forum allows users to ask for help with problems and share their solutions and techniques. The blogs provide a platform for users to publish articles and tutorials on algorithmic topics.

Codeforces is a great resource for programmers who want to practice and improve their algorithmic skills. With its challenging problems, supportive community, and educational resources, Codeforces provides a motivating and engaging environment for programmers of all levels.