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  1. #include <iostream>
  2. #include <unordered_map>
  3. #include <functional>
  4.  
  5. using namespace std;
  6.  
  7. struct Component
  8. {
  9. 	size_t id;
  10. };
  11.  
  12. namespace std
  13. {
  14. 	template<>
  15. 	struct hash<reference_wrapper<Component>>
  16. 	{
  17. 		size_t operator()(const reference_wrapper<Component>& cmp) const
  18. 		{
  19. 			return cmp.get().id;
  20. 		}
  21. 	};
  22. }
  23.  
  24. unordered_map<reference_wrapper<Component>, int> mapping;
  25.  
  26. int main() {
  27. 	// your code goes here
  28. 	return 0;
  29. }
Success #stdin #stdout 0s 3456KB
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https://ideone.com/ZrOege
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

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