如标题，

倒数第二个点答案是0.65

我输出的是0.87

代码如下：

#include <bits/stdc++.h>
using namespace std;
int n,k;
double a[10005];
double l=1,mid,r;
//double maxn (double x,double y){return x>y?x:y;}
double check(double m){
	int cnt=0;
	for (int i=1;i<=n;i++)
		cnt+=a[i]/m;
	return cnt>=k;
}
int main (){
	double sum=0;
	scanf ("%d %d",&n,&k);
	for (int i=1;i<=n;i++) scanf ("%lf",&a[i]),r=max(a[i],r),sum+=a[i];
	if (k>sum){printf ("%0.2lf",floor(sum/k*100)/100.);exit(0);}
	r++;
	while (r-l>=1e-3){
		mid=(l+r)/2.0;
		if (check(mid)) l=mid;
		else r=mid;
	}	
	printf ("%.2lf",l);
}