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  1. #include <iostream>
  2. using namespace std;
  3.  
  4.  
  5. int main() {
  6. 	int t,n,i,j,m;
  7. 	double ans;
  8. 	bool breakk;
  9.  
  10. 	cin>>t;
  11.  
  12. 	while(t--) {
  13. 		breakk=false;
  14. 		cin>>n;
  15. 		double dp[1000][1000]={0};
  16. 		dp[1][1]=1;
  17.  
  18. 		for(i=1;i<998;i++) {
  19. 			for(j=0;j<=i;j++) {
  20. 				if(j<n) {
  21. 					dp[i+1][j+1]+=dp[i][j]*(double(n-j)/n);
  22. 					dp[i+1][j]+=dp[i][j]*(double(j)/n);
  23.  
  24. 					if(dp[i+1][j+1]) {
  25. 						if((j+1==n) && dp[i+1][j+1]<0.00000001) {
  26. 							breakk=true;
  27. 							break;
  28. 						}
  29. 					}	
  30. 				}
  31.  
  32. 			}
  33.  
  34. 			if(breakk) {
  35. 				break;
  36. 			}
  37. 		}
  38. 		ans=0;
  39. 		for(m=n;m<=i+1;m++) {
  40. 			ans=ans+dp[m][n]*m;
  41.  
  42. 		}
  43.  
  44. 		cout<<ans<<endl;
  45. 	}
  46.  
  47. 	return 0;
  48. }
Success #stdin #stdout 0s 10432KB
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https://ideone.com/EzCEn3
language:
C++ 4.3.2 (gcc-4.3.2)
created:
9 years ago
visibility:
public

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