洛谷P5735 【深基7.例1】距離函數經典解法

#include<stdio.h>
#include<math.h>
double d(double x1, double y1,double x2,double y2) {
	return(pow(pow(x1 - x2, 2) + pow(y1 - y2, 2), 0.5));
}
int main(void) {
	double dis, x1, x2, x3, y1, y2, y3;
	scanf("%lf%lf%lf%lf%lf%lf", &x1, &y1, &x2, &y2, &x3, &y3);
	dis = d(x1, y1,x2,y2) + d(x2, y2,x3,y3) + d(x3, y3,x1,y1);
	printf("%.2lf", dis);
	return(0);
}