Well I just found this wierd thing when I was doing the problem Codeforces Round 905 (Div. 3) Prob.D When I use std::find(set.begin(), set.end(), value) or std::lower_bound(set.begin(), set.end(), value), I would get a TLE. But instead of using that, when I replace them with set.find(value) or set.lower_bound(value) it passed smoothly and worked as expected. Why would this happened? Is there any difference between these two approaches?