pku1586.cpp

这是ACM 方面的资料 是PKU的 北京大学的出来的

#include <stdio.h>
#include <math.h>
#define Min 1e-2
int main()
{
	double x[3], y[3], l[3], ang[3], tmp;
	double PI = acos(-1);
	int i, j;
	while (scanf("%lf %lf %lf %lf %lf %lf", &x[0], &y[0], &x[1], &y[1], &x[2], &y[2]) == 6)
	{
		l[0] = sqrt((x[1] - x[2]) * (x[1] - x[2]) + (y[1] - y[2]) * (y[1] - y[2]));
		l[1] = sqrt((x[0] - x[2]) * (x[0] - x[2]) + (y[0] - y[2]) * (y[0] - y[2]));
		l[2] = sqrt((x[1] - x[0]) * (x[1] - x[0]) + (y[1] - y[0]) * (y[1] - y[0]));

		ang[0] = (l[1] * l[1] + l[2] * l[2] - l[0] * l[0]) / (2 * l[1] * l[2]);
		ang[1] = (l[0] * l[0] + l[2] * l[2] - l[1] * l[1]) / (2 * l[0] * l[2]);
		ang[2] = (l[1] * l[1] + l[0] * l[0] - l[2] * l[2]) / (2 * l[1] * l[0]);

		ang[0] = acos(ang[0]) * 180 / PI;
		ang[1] = acos(ang[1]) * 180 / PI;
		ang[2] = acos(ang[2]) * 180 / PI;

		for (i = 0; i < 3; i++)
		{
			for (j = i + 1; j < 3; j++)
			{
				if (l[i] < l[j])
				{
					tmp = l[i];
					l[i] = l[j];
					l[j] = tmp;
				}
				if (ang[i] < ang[j])
				{
					tmp = ang[i];
					ang[i] = ang[j];
					ang[j] = tmp;
				}
			}
		}
		
		if (fabs(l[0] - l[1] - l[2]) < Min)
		{
			printf("Not a Triangle\n");
			continue;
		}

		if (fabs(l[0] - l[2]) < Min)
		{
			printf("Equilateral");
		}
		else if (fabs(l[0] - l[1]) < Min || fabs(l[1] - l[2]) < Min)
		{
			printf("Isosceles");
		}
		else
		{
			printf("Scalene");
		}
		printf(" ");
		if (fabs(ang[0] - 90) < 2)
		{
			printf("Right\n");
		}
		else if (ang[0] > 90)
		{
			printf("Obtuse\n");
		}
		else
		{
			printf("Acute\n");
		}
	}
	printf("End of Output\n");
	return 0;
}