2682911_ac_0ms_88k.c

北大大牛代码 1240道题的原代码 超级权威

#include <stdio.h>
#include <math.h>
#define PI 4.0*atan(1)

double dis(double a,double b,double x,double y)
{
	return sqrt((a-x)*(a-x)+(b-y)*(b-y));
}

int main()
{
	int n, i;
	double r, l;
	double a, b, c, d, x, y;

	scanf("%d%lf",&n,&r);
	scanf("%lf%lf",&a,&b);
	c = a, d = b;
	l = 2.0*PI*r;
	for(i = 1; i < n; i++)
	{
		scanf("%lf%lf",&x,&y);
		l += dis(a,b,x,y);
		a = x,b = y;
	}
	l += dis(a,b,c,d);
	printf("%.2lf\n",l);
	return 0;
}