דיון

Problem Forge has no forum of its own. These are places where people talk about this kind of problem. Each has its own rules; read them before you post. Some ban posts written by AI, and some ask you to say when you used it. Places marked (Discord) are chat servers on Discord; you need a Discord account to read them.

Algorithms and theory

• Computer Science Stack Exchange: algorithms and hard problems.
• Theoretical Computer Science Stack Exchange: research-level questions on complexity and algorithms.
• r/algorithms: designing algorithms.
• r/AskComputerScience: questions about computer science. Beginners are welcome.
• r/compsci: computer science articles and discussion; not for homework help.

Solvers and optimisation

• Operations Research Stack Exchange: optimisation, solvers and the travelling salesperson problem.
• r/OperationsResearch: optimisation and routing.
• OR-Tools discussion group: Google's free solver suite, including CP-SAT.
• MiniZinc discussion group: a language for writing constraint models and running them on many solvers.
• HiGHS discussions: a free solver for linear and integer programs.
• Z3 discussions: Microsoft's free logic solver, which handles SAT and more.
• Gurobi Community: a commercial optimisation solver; modelling and algorithm questions.
• Kaggle Santa competitions: an optimisation contest each December, with a busy discussion board (this link is the 2025 contest).
• Kaggle (Discord): Kaggle's server, with channels for its competitions.
• Google OR-Tools (Discord): chat about OR-Tools and CP-SAT, linked from Google's support page.

AI and LLMs

• r/ChatGPTCoding: coding with AI tools of every kind, not only ChatGPT.
• r/ClaudeAI: using Claude; not run by Anthropic.
• r/ClaudeCode: using Claude Code, an AI coding agent.
• r/OpenAI: OpenAI's models and tools, including Codex; not run by OpenAI.
• r/cursor: the Cursor AI code editor.
• r/GithubCopilot: GitHub Copilot; not run by GitHub.
• r/LocalLLaMA: running AI models on your own computer.
• r/LLMDevs: building programs that use language models.
• r/MachineLearning: machine learning research; beginner questions go elsewhere.
• Hugging Face Forums: open AI models and tools; has a beginners section.
• OpenAI Developer Community: building with OpenAI's API and Codex.
• Claude (Discord): Anthropic's server for Claude and Claude Code.
• OpenAI (Discord): OpenAI's server for ChatGPT, Codex and its models.
• Hugging Face (Discord): open AI models and tools.
• Google Developer Community (Discord): Google's developer server; Gemini has its own channels.
• DeepSeek (Discord): the DeepSeek models.
• Ollama (Discord): running open models on your own computer with Ollama.

Programming

• Stack Overflow: questions about specific code.
• Code Review Stack Exchange: ask others to review working code.
• r/learnprogramming: programming questions in any language; beginners welcome.
• r/programming: programming articles and news; AI tools are mostly off-topic.
• r/cpp: the C++ language.
• r/C_Programming: the C language.
• r/rust: the Rust language.
• Together C & C++ (Discord): help and discussion on C and C++.
• Rust Community (Discord): learning and using Rust; not run by the Rust project.
• Python (Discord): the Python language; beginners welcome.
• Hacker News: links and discussion on programming and technology.
• Lobsters: links and discussion on programming; joining needs an invitation.

Contests and puzzles

• r/adventofcode: the forum of Advent of Code, a yearly puzzle event. Most posts are about Advent of Code.
• r/everybodycodes: forum of Everybody Codes, a yearly puzzle event like Advent of Code.
• Codeforces: programming contests, with blogs where people discuss problems.
• USACO Guide (Discord): the server of the USACO Guide's authors, for competitive programming.
• CodinGame (Discord): puzzles, bot contests and quick "clash" rounds on CodinGame.
• Project Euler: math and programming problems; each problem has a discussion thread that opens once you solve it.
• Code Golf Stack Exchange: contests for the shortest or fastest program.
• Puzzling Stack Exchange: logic puzzles and how to solve them.
• r/puzzles: sharing and solving puzzles of all kinds.
• r/dailyprogrammer: an archive of several hundred programming challenges with their discussions; no longer updated.

Mathematics

• Mathematics Stack Exchange: graphs, sums and counting, at any level.
• MathOverflow: research-level math only.
• r/math: discussion of mathematics; simple questions go in its weekly thread.
• r/askmath: math questions at any level.
• Mathematics (Discord): learning and discussing mathematics, from school level to research.