CodeForces is one of the most popular websites among competitive programmers, hosting regular contests where participants must solve challenging algorithmic optimization problems. The challenging nature of these problems makes them an interesting dataset to improve and test models’ code reasoning capabilities. This dataset includes more than 10k unique problems covering the very first contests all the way to 2025.… See the full description on the dataset page: https://huggingface.co/datasets/open-r1/codeforces.