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  1. #include <deque>
  2. #include <random>
  3. #include <algorithm>
  4. #include <cmath>
  5. #include <iostream>
  6.  
  7. int countTo24(std::mt19937& gen, std::uniform_int_distribution<>& dist)
  8. {
  9. 	bool found[24] = {0};
  10. 	int remaining = 24;
  11. 	int attempts;
  12. 	for (attempts = 0; remaining != 0; attempts++)
  13. 	{
  14. 		int random = dist(gen);
  15. 		if (!found[random])
  16. 		{
  17. 			found[random] = true;
  18. 			remaining--;
  19. 		}
  20. 	}
  21. 	return attempts;
  22. }
  23.  
  24. int main()
  25. {
  26. 	int randomState[16];
  27. 	std::seed_seq seed(std::begin(randomState), std::end(randomState));
  28. 	std::mt19937 gen(seed);
  29. 	std::uniform_int_distribution<> dist(0, 23);
  30.  
  31. 	std::deque<int> counts;
  32. 	for (int i = 0; i < 100000; i++)
  33. 	{
  34. 		counts.push_back(countTo24(gen, dist));
  35. 	}
  36.  
  37. 	long long averageAcc = 0;
  38. 	for (int count : counts) averageAcc += count;
  39. 	double average = averageAcc / (double)counts.size();
  40.  
  41. 	long long varianceAcc = 0;
  42. 	for (int count : counts)
  43. 	{
  44. 		int diff = count - average;
  45. 		varianceAcc += diff * diff;
  46. 	}
  47. 	double variance = varianceAcc / (double)counts.size();
  48. 	double stdDev = sqrt(variance);
  49.  
  50. 	std::cout << "avg: " << average << std::endl;
  51. 	std::cout << "stddev: " << stdDev << std::endl;
  52. }
Success #stdin #stdout 0.53s 3476KB
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stdin
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Standard input is empty
stdout
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avg: 90.6073
stddev: 28.4351
https://ideone.com/NRTJRo
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
public

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