Order of including headers seems to affect overall running time.

Difference between en1 and en2, changed 38 character(s)

I wrote two different codes, which differs only on order of headers.↵
Two codes are like these:↵
↵
1. ↵
↵
~~~~~↵
#include <stdio.h>↵
#include <algorithm>↵
....(blahblah)....↵
↵
2.~~~~~↵
↵
↵
2.↵
↵
~~~~~↵
↵
#include <algorithm>↵
#include <stdio.h>↵
....(blahblah)....↵
~~~~~↵
↵
↵
Note: At (blahblah) part, there are 9 millions scanf("%d", &t) operations.↵
Compilation options are both GNU C++14. (GNU C++14 6.2.0, which is used on Codeforces.)↵
↵
For my opinion, this two code should exactly do the same operations.↵
↵
But, 1st code gives 1.6ms / 2ms AC, and 2nd code gives TLE.↵
This issue is not about server status, it's still same during many submits.↵
↵
Can someone help me about what's going on here?

History

Revisions

Rev.	By	When	Δ	Comment
en3	dotorya	2017-04-04 17:51:30	47	Tiny change: 'g on here?' -> 'g on here?\n\nNote : It's not 1.6ms / 2ms, It's 1.6s / 2s'
en2	dotorya	2017-04-04 17:36:25	38
en1	dotorya	2017-04-04 17:35:40	726	Initial revision (published)