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  1. #include <iostream>
  2. #include <vector>
  3. #include <map>
  4. #include <cstdlib>
  5.  
  6. std::vector<int> generate_numbers(int amount, int max_num)
  7. {
  8. 	std::vector<int> numbers(amount);
  9. 	for (int i = 0; i < amount; ++i) {
  10. 		numbers[i] = rand() % max_num + 1;
  11. 	}
  12. 	return numbers;
  13. }
  14.  
  15. std::map<int, int> count_numbers(const std::vector<int> &numbers)
  16. {
  17. 	// Count numbers
  18. 	std::map<int, int> counts; // We will store the count in a map for fast lookup (C++11's unordered_map has even faster lookup)
  19. 	for (size_t i = 0; i < numbers.size(); ++i) { // For each number
  20. 		counts[numbers[i]]++; // Add 1 to its count
  21. 	}
  22. 	return counts;
  23. }
  24.  
  25. void print_counts(const std::map<int, int> &counts)
  26. {
  27. 	for(std::map<int, int>::const_iterator it = counts.begin();
  28. 	it != counts.end();
  29. 	++it) { // For each number stored in the map (this automatically filters those with count 0)
  30. 		std::cout << it->first << ": " << it->second << std::endl; // Output its count
  31. 	}
  32. }
  33.  
  34. int main() {
  35. 	srand(0); // So that we get the same result every time
  36. 	std::vector<int> numbers = generate_numbers(10000, 500);
  37. 	std::map<int, int> counts = count_numbers(numbers);
  38. 	return 0;
  39. }
Success #stdin #stdout 0s 3464KB
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https://ideone.com/2NyY8K
language:
C++ (gcc 8.3)
created:
10 years ago
visibility:
public

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