IIRC, there’s some error with the listed Constraints for this Problem: at the time of writing, the Problem Statement says:
but there are some comments that suggest that this is wrong e.g. CONFLIP - Editorial - #15 by the65bit.
If N can be as high as 10^9, declaring a local array of size N will almost certainly cause a crash.
I definitely can’t see any reason for a RE if N\le10.
Ok Im ready to skip this