题解 | 绕距

#include <stdio.h>
#include <math.h>
#include <stdlib.h>

int main() 
{
    int x1 ,y1,x2,y2;
    double dm,de;
    scanf("%d %d %d %d",&x1,&y1,&x2,&y2);
    dm=fabs(x1-x2)+fabs(y1-y2);
    de=sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));
    printf("%1f",dm-de);
    return 0;
}