I'm not too familiar with C++ syntax, but I would guess than the line: cin>>x; reads in a whole line since there are no white spaces, thus storing all n lines in the first vector (so all the other three are empty and therefore equal). When you did it on your compiler did you separate the 1's and 0's by white spaces?

Cin reads long long without trailing zeros. Change X to char. ACCEPTED

You are reading integers of type long long with cin >> x,but in input you have N binary strings.