When I was submitting the problem D in round #371, I clicked the "Choose File" button and selected my code.

Before the submission, I read my code another time, found a bug in my code and fixed it. And then I clicked the "submit" button.

But it turned out that my solution got wrong answer on pretest 4. I stress-tested my solution, and found it passed the big random data. I was really shocked. umm... Maybe my solution failed on some small testcases. So I tried many ways to generate testcases. But my solution was right on all the testcases I generated.

After struggling for about 40mins, I gave up and submitted it again. It passed all the pretests.

I compared two codes, and just found I submitted the old version (before fixing the bug) at first time.

After asking my roommate, he said when you clicked the "Choose File" button, it would upload the file instead of recording the path.

In the rest time of the contest, I tried to solve problem B and E but failed.

I think I should quit from Algorithm contest like YuukaKazami and study harder.<\S>