[file removed by admin]
All of Bartok's works that he wrote prior to the beginning of WWII are public domain, at this point, due to a dispute he had with his publisher in the 30's and Hungary's copyright laws that allowed it to enter public domain prior to the EU forming.
Either way, this score is quite easy to find with a bit of googling, and I'm not going to upload it if the admins are going to complain about it.
However, it's all a non-point. In the huge majority of cases, any sort of score-sharing is illegal, because the publisher owns the right to their edition of the publication. Whether the piece is in public domain does not matter. If anyone cared, any of the sites like the IMSLP could be shut down and sued. The whole worry over whether the piece is in public domain is malapropos to the legality of sharing the score.