For C++ it would be nice to know what compiler is being checked against. At least in the demo question I would use a 64 bit int to hold the sum if the arrays are really "large" but MSVC names the type __int64 vs G++ using long long and other such minor details. Same for the other languages aka python 2.x or 3.x etc.
We want to avoid sticking to particular compilers/interpreters. An expert in MSVC should not be penalized only because we use GCC. Also we design the tasks so that they are compiler-agnostic (actually they are even language-agnostic). It is sometimes a bit tricky due to non-standardized type sizes (e.g. C, C++, PHP), but generally the tasks can be solved using very limited and portable subset of a language.
