HDU 1551 Cable master

题解：很显然的二分检索，在算法艺术上看过原题，不过这里要注意精度：

#include <cstdio>  

int n,m;  



double a[10001];  

bool test(double x){  

    int num=0,i;  

    for(i=1;i<=n;i++)num+=int(a[i]/x);  

    if(num>=m){  

        return true;  

    }else{  

        return false;  

    }  

}  

  

int main()

{  

    while(scanf("%d%d",&n,&m),n||m){  

            int i ;  

            double sum=0;  

            for(i=1; i<=n; ++i){  

            scanf("%lf",&a[i]);  

            sum+=a[i];  

        }  

        double max=sum/m,l=0,r=max;  

        while(r-l>1e-10){  

            double mid = (l+r)/2;  

            if(test(mid)){  

                l=mid+1e-11;  

            }else{  

                r=mid-1e-11;  

            }  

        }  

        printf("%.2lf\n",(l+r)/2);  

    }  

}