AtCoder vs Yandex Contest

AtCoder is a free web service for competitive programming contests and practice. Users solve programming problems in Algorithm Contest and Heuristic Contest formats, and can run source code in a browser rather than setting up a local programming environment. Its practice library contains about 5,000 past problems with explanations, and it supports nearly all major programming languages, including C++, Python, Rust, Java, and C#. Beginner Contests take place weekly, Regular Contests about monthly, Grand Contests five to six times a year, and heuristic contests about monthly. Real-time participation in Algorithm or Heuristic contests changes a user's AtCoder rating. AtCoder Jobs lets users apply to companies using their rating for roles including internships and experienced positions. PAST is an online algorithm skills test available in Japanese and English, with problems updated every six months. AtCoder says it has about 200,000 registered users and about 10,000 participants in real-time contests weekly. Its terms limit members to one account and prohibit account sharing, lending, or transfer.

Yandex Contest is a free online platform for programming competitions, practice, and lessons with automatic solution checking. Organizers can create problems or select ready-made sets, then configure rules, deadlines, ratings, and invitations. Contests support individual or team participation and may be open or restricted. A testing server evaluates submissions according to contest rules. The platform lists more than 20 programming languages, with compiler settings for supported languages, and its demo includes checker-based, interactive, run-twice, test, text-answer, and matching problems. The public API uses OAuth permissions to register participants, manage groups, retrieve contest and problem details, submit or rejudge solutions, and export leaderboards. Users sign in with Yandex ID or organizer credentials. The organizer plan is free for up to 10,000 participants; organizers expecting more must contact Yandex. Full administrator-panel access requires a form.