While solving Goodbye 2015, E i was getting TL on test 11. Now after the contest I decided to see what was the problem.
After some debugging I found that when you do lower bound on an empty set it gives TL:
http://mirror.codeforces.com/contest/611/submission/15127498 — AC
http://mirror.codeforces.com/contest/611/submission/15126396 — TL11
The only difference is ans if(s.size() == 0) break;
So I want to ask if there are similar issues with the std::set.