I think another reason is that for the competition-kind code there is very little difference between languages, so the drawbacks of C++ just don't matter. For e

I think another reason is that for the competition-kind code there is very little difference between languages, so the drawbacks of C++ just don't matter. For example, the lack of garbage collection is not a problem, as the program works in the "allocate-compute-free" workflow. And with C++ you have far more room before you would have to think about performance than with more high-level languages. That is, maybe counterintuitively for someone, programming on C++ may be easier when performance matters.