题解 | 绕距

#include<stdio.h>

#include<math.h>

int main()

{

int x1, x2, y1, y2;

scanf("%d%d", &x1,&y1 );

scanf("%d%d", &x2, &y2);

double de, dm, a;

de = sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));

dm = fabs(x1 - x2) + fabs(y1 - y2);

a = fabs(dm - de);

printf("%.12lf", a);

return 0;

}