In the latest contest, i got trouble in problem H.
When i want to compare x is lager than y, i use x>y+eps (i learn this from a book), but i get WRONG ANWSER , but when i just use x>y ,then i accept .
I just wonder which one is true. Thx first.

I search it in google , but i can't find it. Can somebody tell me how to use lower_bound in set<pair<int,int>> , so i can find the fist pair whose first element is not small than the element i search for ?