Are llvm-gcc and gcc compatible?

Question

GCC

I now want to participate in one programming competition, and there is one of the requirements that the solution be compiled by the MinGW GNU C ++ 4 compiler (as I understand it, this is the same gcc). I have an iMac myself and plan to develop solutions in xCode 5.x. Hence my question.
I would like to know how compatible these compilers are?
For example, code written in C++ under llvm-gcc will compile and run on MinGW GNU C++ 4 (gcc)?

Answer 1

Use only standard language elements and this code will work anywhere