How do I avoid rehashing overhead with std::vector in performance-sensitive code?

In performance-sensitive C++ code, avoiding rehashing overhead with std::vector requires careful management of capacity and size. The rehashing process can be costly, especially when dealing with large datasets. Below, we explain strategies to minimize this overhead and provide an example to illustrate these techniques.

#include #include int main() { // Create an empty vector and reserve space std::vector vec; vec.reserve(10000); // Preallocate space for 10,000 elements to avoid rehashing for (int i = 0; i < 10000; ++i) { vec.push_back(i); // Add elements } std::cout << "Vector size: " << vec.size() << std::endl; std::cout << "Vector capacity: " << vec.capacity() << std::endl; return 0; }

C++ std::vector performance rehashing optimization capacity management

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