Whitespace matters! Their checking programs are strange.
If the answer is "1 2 3",
printf("1 2 3 \n");
is wrong answer, while
printf("1 2 3");
is accepted.

oh,my god,why they didnt produce a "presentation error"
instead of the "Wrong answer"....

matter is the '\n'
my solution get wrong answer with a '\n'
and get accept without it

matter is endl, but I don't know the program they wrote to
check is so sensitive to these minor details,

From Now on I won't add any extra endl to my output,