We all know that this line in C++#pragma GCC optimize("Ofast") can optimize most programs.

But specially, the accident(maybe?) happens on me.

Today, I was solving the problem 455D - Serega and Fun with fhq-treap, And I submitted two submissions: 58122597 and 58123225, when first one got AC with no optimization, and the second with 'Ofast' optimization got TLE on test 25.

So I just want to know what kind of programs the 'Ofast' optimization can bring negative optimization?