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  1. #include <iostream>
  2. #include <vector>
  3. #include <map>
  4. #include <string>
  5.  
  6. template<typename Key, typename Val>
  7. class OrderedMap
  8. {
  9. private:
  10. 	std::vector<std::pair<Key, Val>> ordered;
  11. 	std::map<Key, std::size_t> lookup;
  12.  
  13. public:
  14. 	void insert(Key k, Val v)
  15. 	{
  16. 		ordered.push_back(std::pair<Key, Val>(k, v));
  17. 		lookup.emplace(k, ordered.size() - 1);
  18. 	}
  19.  
  20. 	Val find(Key k)
  21. 	{
  22. 		std::size_t index = lookup[k];
  23. 		return ordered[index].second;
  24. 	}
  25.  
  26. 	// "typename" needed as the "iterator" is a dependent type
  27. 	typename std::vector<std::pair<Key, Val>>::iterator begin()
  28. 	{
  29. 		return ordered.begin();
  30. 	}
  31. 	typename std::vector<std::pair<Key, Val>>::iterator end()
  32. 	{
  33. 		return ordered.end();
  34. 	}
  35. };
  36.  
  37. int main()
  38. {
  39. 	OrderedMap<std::string, int> m;
  40. 	m.insert("1", 1);
  41. 	m.insert("2", 2);
  42. 	m.insert("3", 3);
  43.  
  44. 	std::cout << m.find("2") << std::endl << std::endl;
  45.  
  46. 	for (auto i = m.begin(); i != m.end(); i++)
  47. 		std::cout << i->first << " " << i->second << std::endl;
  48. 	std::cout << std::endl;
  49.  
  50. 	return 0;
  51. }
Success #stdin #stdout 0s 4560KB
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https://ideone.com/SPfYeY
language:
C++ (gcc 8.3)
created:
6 years ago
visibility:
public

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