poj 1064 Cable master

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cmath>
using namespace std;
const int maxn=1e4+5;
const double esp=1e-9;
double c[maxn];
int n,k;

bool judge(double mid){
    int cnt=0;
    for(int i=0;i<n;i++)
      cnt+=(int)(c[i]/mid);
    return cnt>=k;
}

int main(){
    while(~scanf("%d%d",&n,&k)){
        double l=0,r=0;
        for(int i=0;i<n;i++){
            scanf("%lf",c+i);
            r+=c[i];
        }
        r/=k;
        while(r-l>esp){
            double mid=(l+r)/2;
            if(judge(mid))
              l=mid;
            else
              r=mid;
        }
        r=floor(r*100)/100;
        printf("%.2f\n",r);
    }
    return 0;
}