> #include <cstdio>
> #include <cstring>
> // #include <algorithm>
> // #include <cassert>
> // using std::sort;
> #include <cmath>
> #define f(x,y,z) for(int x = (y),__ = (z);x < __;++x)
> #define g(x,y,z) for(int x = (y),__ = (z);x <= __;++x)
> #define fd(x,y,z) for(int x = (y),__ = (z);x > __;--x)
> #define gd(x,y,z) for(int x = (y),__ = (z);x >= __;--x)
> #define MAX 10024
> #define EPS 1e-6
> int n,k;
> double len[MAX];
> double ll = 0.0,rr,m(0.0);
> inline bool check(double x){
> 	int tee = 0;
> 	f(i,0,n){
> 		tee += (int)(len[i] / x);
> 	}
> 	return tee >= k;
> }
> double sum,max;
> int main(){
> 	scanf("%d%d",&n,&k);
> 	f(i,0,n){
> 		scanf("%lf",&len[i]);
> 		sum += len[i];
> 		if (max < len[i])max = len[i];
> 	}
> 	if (sum * 100 < k){
> 		puts("0.00");
> 		return 0;
> 	}
> 	rr = max;
> 	while (rr - ll > EPS){
> 		// m = ll + (rr - ll) / 2;
> 		m = (ll + rr) / 2.0;
> 		if (check(m))ll = m;
> 		else rr = m;
> 	}
> 	// if (ll >= 0.01)printf("%.2lf\n",ll);
> 	if (rr >= 0.01)printf("%.2lf\n",floor(rr * 100) / 100);
> 	// if (rr >= 0.01)printf("%.2lf\n",rr);
> 	else puts("0.00");
> 	return 0;
> }
> 
> 以上代码是二分的
> AC
> 可是如果是把while循环改成for循环(100次)，能过样例但是WA；
> 如果改成200次就连样例都过不了了…………