64-bit integers and printf/scanf

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Information for C users: input and output of 64-bit integers is slightly different between Windows and Linux.

On Linux (in particular, on the grading server) GCC uses the implemantations of printf and scanf from the GNU library glibc where the format string for 64-bit signed integers (long long) is %Ld or %lld and the format string for 64-bit unsigned integers (unsigned long long) is %Lu or %llu.

On Windows (in many computer labs) both MSVC (the compiler of Visual Studio) and GCC/MinGW (the default compiler of Code::Blocks) use the implementations of printf and scanf from the Microsoft library MSVCRT.DLL where the format string for 64-bit signed integers is %I64d or %lld and the format string for 64-bit unsigned integers is %I64u or %llu.

For your solution to work correctly in both environments, it's best to always use %lld and %llu.

This applies also to using printf and scanf in C++ code, but does not affect the use of the streams library in C++ (the cin, cout, and cerr objects and the ifstream and ofstream classes).

The input and output operations of Pascal, Java, and Python have no difference between Windows and Linux.