代码：

#include<iostream>

#include<algorithm>
#include<iomanip> 

using namespace std;
int main()
{
	
	double k, max = 0.1;
	int n;
	double he = 0;
	cin >> n >> k;
	double a[n + 5];
	
	for(int i = 1; i <= n; i++)
	{
		cin >> a[i];
		he += a[i];
		
		if(max < a[i])
		{
			max = a[i];
		}
	}
	
	if(he < k)
	{
		cout << 0;
		return 0;
	}
	
	int L = 1, R = max;
	
	while(L < R)
	{
		double cnt = 0;
		
		int mid = (L + R + 1) / 2;
		
		for(int j = 1; j <= n; j++)
		{
			cnt += a[j] / mid;
		}
		
		if(cnt == k)
		{
			L = mid;
		}else if(cnt < k)
		{
			R = mid - 1;
		}else
		{
			L = mid;
		}
	}
	cout << setprecision(2) << fixed << L * 1.00;
	
	return 0;
}

为什么#3，9，10，11，12，13都wa？