I don't think the tests for the problem are very hard. Using Haskell my program solves this in about 0.5 secs but gets an AC in .031 secs (which I think is the lowest time you can get now), so they could definitely make the problems harder.
I don't know, my program passes this test in 0.001341s. on my local PC. I got AC in 0.015s. The tests for this program are probably just fine. The Haskell program could be compiled without optimizations or someone has a wooden PC.
