第五组样例：

23.234 12.123
-99.99 99.99
-1 -100

样例输出：

489.20

我的输出：

489.20

我的代码：

#include<cstdio>
#include<algorithm>
#include<cmath>
double A;
struct xy {
	double x;
	double y;
};
double dis(double x, double y, double x1, double y1, double x2, double y2) {
	return sqrt(pow(abs(x - x1), 2) + pow(abs(y - y1), 2)) + sqrt(pow(abs(x1 - x2), 2) + pow(abs(y1 - y2), 2)) + sqrt(pow(abs(x2 - x), 2) + pow(abs(y2 - y), 2));
}
int main() {
	xy a, b, c;
	scanf("%lf %lf\n%lf %lf\n%lf %lf", &a.x, &a.y, &b.x, &b.y, &c.x, &c.y);
	A = dis(a.x, a.y, b.x, b.y, c.x, c.y);
	if (floor(A) == A)printf("%d", int(A));
	else if (floor(A * 10) == A * 10)printf("%.1lf", A);
	else printf("%.2lf", A);
	return 0;
}