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  1. #include <iostream>
  2. #include <random>
  3. #define N 75
  4. #define TRIALS 1000000
  5.  
  6. int main() {
  7. 	int counter[2*N];
  8. 	for (int i = 0; i < 2*N; ++i)
  9. 		counter[i] = 0;
  10. 	std::random_device rd;
  11. 	std::mt19937 gen(rd());
  12. 	std::uniform_int_distribution<> dis;
  13. 	int count = 0;
  14. 	const int A = 52;
  15. 	for (int trial = 0; trial < TRIALS; ++trial) {
  16. 		int whites = 0;
  17. 		dis = std::uniform_int_distribution<> (0, N);
  18. 		for (int i = 0; i < N; ++i) {
  19. 			whites++;
  20. 			if (dis(gen) < whites) {
  21. 				--whites;
  22. 				++counter[i];
  23. 				//++count;
  24. 			}
  25. 		}
  26. 		/*for (int i = A; i < N+A; ++i) {
  27. 			dis = std::uniform_int_distribution<> (0, 2*N-i-1);
  28. 			if (dis(gen) < whites) {
  29. 				--whites;
  30. 				++counter[i];
  31. 			}
  32. 		}*/
  33. 		count += whites;
  34. 	}
  35. 	/*for (int i = 0; i < 2*N; ++i)
  36. 		std::cout << i << ' ' << (double)counter[i] / TRIALS << '\n';*/
  37. 	std::cout << (double)count / TRIALS / N << '\n';
  38. 	return 0;
  39. }
Success #stdin #stdout 1.51s 15240KB
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0.629711
https://ideone.com/7ZU9l1
language:
C++14 (gcc 8.3)
created:
5 years ago
visibility:
public

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