I took part in CF 644 (CROC Qualification challenge) and noticed that though Problem B was trivial, my code failed at pretest 8.
After the contest I looked up the thorny test case, which was:
8 3
1 2
3 1
4 3
5 3
6 1
7 2
8 8
9 7
with correct output as
3 4 7 10 11 13 21 28
Shockingly, my own local machine environment (G++11 5.3.0, win32) and CF Custom Invocation (G++11 5.1.0) gave the correct output for my submission. Yet CF Submission grader (also G++11 5.1.0) gives me a WA (with the output:)
3 4 7 10 11 13 21 -1
I have absolutely no explanation for this oddity (WTH???). This very well did not cost me my qualification for CROC 16. But had it been a different round, I would be very sad.
Can anyone tell me what possibly might be wrong with
1. My code? Relevant submissions are #16753691 and #16872103 OR
2. CF Submission Grader or Custom Invocation for G++11 5.1.0?
PS: I noticed that this is probably not the first time something remotely similar has happened (ref. for e.g. CF Blog 8848), but even then the Custom Invocation and Submission Grader outputs always match.
