#include <stdio.h>
#include <math.h>

int n;
double point[660][2];
double dis[660][660];

int main()
{
	int cas;
	int i, j, k;
	double ans, tmp;
	double a, b, c;

	scanf("%d", &cas);
	while (cas-- > 0)
	{
		scanf("%d", &n);
		ans = 0.0;
		for (i = 0; i < n; i++)
		{
			scanf("%lf%lf", &point[i][0], &point[i][1]);
		}
		for (i = 0; i < n; i++)
		{
			for (j = i + 1; j < n; j++)
			{
				dis[i][j] = sqrt((point[i][0]-point[j][0])*(point[i][0]-point[j][0])+(point[i][1]-point[j][1])*(point[i][1]-point[j][1]));
			}
		}
		for (i = 0; i < n; i++)
		{
			for (j = i + 1; j < n; j++)
			{
				for (k = j + 1; k < n; k++)
				{
					a = dis[i][j];
					b = dis[i][k];
					c = dis[j][k];
					tmp = a*b*c/sqrt((a+b+c)*(a+b-c)*(a+c-b)*(b+c-a));
					if (tmp > ans)
					{
						ans = tmp;
					}
				}
			}
		}
		printf("%.3lf\n", ans);
	}
	return 0;
}

• Re:我怎么WA了？这个公式不对么？ (1059) ccnu_xieshuo 2008-05-06 20:04:05