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  1. #include <iostream>
  2. #include <chrono>
  3. #include <vector>
  4. #include <type_traits>
  5.  
  6. struct S {
  7. 	int hui;
  8. 	double pizda;
  9. 	short dzhigurda;
  10. };
  11.  
  12. template <typename T> struct uninitialized_allocator {
  13. 	using value_type = T;
  14.  
  15. 	template<typename U, typename... Args>
  16. 	void construct(U * const ptr, Args&&... args) {}
  17.  
  18. 	T* allocate(size_t n) {
  19. 		return allocator.allocate(n);
  20. 	}
  21.  
  22. 	void deallocate(T* const ptr, size_t n) {
  23. 		allocator.deallocate(ptr, n);
  24. 	}
  25.  
  26. 	std::allocator<T> allocator;
  27. };
  28.  
  29. int main() {
  30.  
  31. 	auto t = std::chrono::system_clock::now();
  32. 	std::vector<S> v1(1000000);
  33. 	std::cout << std::chrono::duration<double, std::milli>(std::chrono::system_clock::now() - t).count() << std::endl;
  34.  
  35. 	t = std::chrono::system_clock::now();
  36.  
  37. 	std::vector<S, uninitialized_allocator<S>> v2(1000000);
  38. 	std::cout << std::chrono::duration<double, std::milli>(std::chrono::system_clock::now() - t).count() << std::endl;
  39.  
  40. 	return 0;
  41. }
Success #stdin #stdout 0.02s 26396KB
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10.205
0.008616
https://ideone.com/9Jeu4g
language:
C++ (gcc 8.3)
created:
6 years ago
visibility:
public

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