Post here if you don't find any other place for your post. But please, stay on-topic: algorithms, programming or something related to this web site and its services.
If I'm not mistaken, Valladolid Online Judge policy is that all problems have 10s of running time, unless there's an explicit request from the problemsetter. A lot of problemsetters add more inputs to their program, so that "way-too-brute-force" approaches don't work.