Codeforces is an online platform for algorithms and programming contests, offering timed contests, a rich problemset, and an active community, supporting many programming languages and live rankings. Suitable for systematic improvement of algorithm skills, interview preparation, and classroom teaching.
virtual contest, online practice, live standings, and post-submission hack flowsAPI and a problem management tool (Polygon) for creating and reviewing contestsHigh-frequency contests with instant scoring, a vast tag-filterable problemset, active community discussions and authoritative editorials, plus support for online head-to-heads and custom contest formats — making it the top choice to boost algorithm skills and evaluate practical performance.