Hi everyone! Many saw entry of user Zlobober which stated that the Thue-Morse string with terrifying force knocks hash modulo 2^64 . Single hashes were too unsafe because of the birthday paradox. The only remaining salvation from infernal suffix structures was double hashing. However, soon it will come to an end. Thoroughly studying Thue-Morse string and its possible modifications, I came to the conclusion that the test that breaks even double hash solutions is possible.

Here I described in detail the construction of the test, its use against real solutions from various contests and proof of its work.

Now I propose to users of codeforces to discuss what to do in this situation. Is there really no more ways to solve the problems with polynomial hash? Who has any thoughts on this?