Good day to you. I am an experienced C/C++ programmer and — let me clarify why I have made a bid greater that the budget, but I have the reasons for that. Basically your program need to be both correct and quick, right? I think I can help you to make your program very quick and very efficient. I can add caching and pre-memory allocation, parallelization and, the most important (the reason why I am making a bid larger than 30 AUD) — I shall implement quick power algorithm and quick matrix multiplication algorithm (Strassen algorithm). This way, I think, you'll receive a lot of marks for performance.
Price is subject to change depending on what do you actually need to be done.
Good luck in choosing your best freelancer!