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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3. #define eps 1e-4
  4. double a,b,c;
  5. bool check(double x){
  6. 	double sum=0,t=1;
  7. 	for(int i=1;i<=c;i++){
  8. 		t/=(1+x),
  9. 		sum+=t;
  10. 	}
  11. 	return sum>1.0*a/b;
  12. }
  13. int main(){
  14. 	cin>>a>>b>>c;
  15. 	double r=5,l=0,ans=0;
  16. 	while(r-l>eps){
  17. 		double mid=(r+l)/2;
  18. 		if(check(mid)){
  19. 			l=mid;
  20. 			ans=mid;
  21. 		}else{
  22. 			r=mid;
  23. 		}
  24. 	}
  25. 	printf("%.1lf",ans*100);
  26. 	return 0;
  27. }
Success #stdin #stdout 0s 5316KB
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2.9
https://ideone.com/4D9LQs
language:
C++ (gcc 8.3)
created:
6 days ago
visibility:
public

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