How do I reserve capacity ahead of time with std::unordered_map for large datasets?

When dealing with large datasets in C++, it's important to optimize data structures for performance. One way to enhance the performance of an `std::unordered_map` is by reserving its capacity ahead of time. This prevents multiple reallocations as you insert elements, making the process more efficient.

Example: Reserving Capacity for std::unordered_map

#include #include int main() { // Create an unordered_map std::unordered_map myMap; // Reserve space for 1000 elements myMap.reserve(1000); // Insert elements for (int i = 0; i < 1000; ++i) { myMap[i] = "Value " + std::to_string(i); } // Output the size std::cout << "Size of myMap: " << myMap.size() << std::endl; return 0; }

C++ std::unordered_map reserve capacity performance optimization large datasets programming data structures.

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