Google Code Jam 2014 Qualification Round B

1、用贪心法做。。。

#include<cstdio>

#include<algorithm>
#include<cmath>
using namespace std;
const double eps=1e-9;
double dcmp(double x){ 
    if(fabs(x)<eps) return 0;
if(x>0) return 1;
return -1;
}
int main(){ 
//freopen("B--large.in","r",stdin);
//freopen("B--large.out","w",stdout);
    int T;
double C,F,X;
scanf("%d",&T);
for(int kase=0;kase<T;kase++){ 
    scanf("%lf%lf%lf",&C,&F,&X);
double now=2,time=0;
while(1){
        double t1=C/now+X/(now+F);
    double t2=X/now;
    if(dcmp(t1-t2)<0){          
        time+=C/now;
    now+=F;
    }else{ 
        time+=t2;
break;
    }
}
printf("Case #%d: %.7f\n",kase+1,time);
}
return 0;
}