Hello!
In this problem in original ML is 256 Mb But on Timus it is 64... Maybe admins have to increase it?

Yes, the problem is much more challenging now than it was originally, but it is still solvable. We will not increase memory limit.

OK, I have solved it with less than 32Mb and faster than 1sec. BUT! Can anybody expalin HOW it is possible to solve it with ~0.1 sec and ~2Mb????

I think, one may use the same trick, but twice

In international contests just them
would be paid for unexpected skills and mastering.