I have submitted two exactly similar solutions for Java, the following:
https://www.codechef.com/viewsolution/11885890
https://www.codechef.com/viewsolution/11885863
If you see the submission status of each of the solutions, the first got AC whereas the second got RE with NZEC error.
On copy pasting the files and seeing diff, there aren’t any. The only difference is that one of the solution was submitted earlier.
I’m no expert in this, but I believe it has something to do with the custoimzed input class I’m using which fails to create an object on the first compilation.
The ACM ICPC regionals are just around the corner, so I just want the admin to look into it as there will be a 20 min penalty for getting an RE even when there was no error of the participant.