题解 | 绕距

#include <stdio.h>
#include <math.h>
int main()
{
    int x1,x2,y1,y2;
    double de,dm;
    scanf("%d %d",&x1,&y1);
    scanf("%d %d",&x2,&y2);
    de=sqrt(pow(x1-x2,2)+pow(y1-y2,2));
    dm=fabs(x1-x2)+fabs(y1-y2);
    double det=fabs(dm*1.0-de);
    printf("%lf",det);
    return 0;
}