pku1064.cpp

这是ACM 方面的资料 是PKU的 北京大学的出来的

#include <stdio.h>
#define SIZE 11000
int Cable[SIZE];
int N, K;

__int64 part(__int64 l)
{
	__int64 ans;
	int i;
	for (i = 0, ans = 0; i < N; i++)
	{
		ans += Cable[i] / l;
	}
	return ans;
}

void Solve()
{
	int i;
	double a;
	__int64 high, low, mid;
	__int64 cnt, sum;
	for (i = 0, sum = 0; i < N; i++)
	{
		scanf("%lf", &a);
		Cable[i] = (int)(a * 100);
		sum += Cable[i];
	}
	if (sum < K)
	{
		printf("0.00\n");
		return;
	}
	low = 1;
	high = sum / K;
	while (low + 1 < high)
	{
		mid = (low + high) / 2;
		cnt = part(mid);
		if (cnt < K)
		{
			high = mid;
		}
		else
		{
			low = mid;
		}
	}
	if (part(high) >= K)
	{
		printf("%.2lf\n", high * 0.01);
	}
	else
	{
		printf("%.2lf\n", low * 0.01);
	}
}	

int main()
{
	while (scanf("%d %d", &N, &K) != -1)
	{
		Solve();
	}
	return 0;
}