题解 | 绕距

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

int main() {
    int x1,y1,x2,y2;
    float dE,dM,det;
    scanf("%d %d\n%d %d",&x1,&y1,&x2,&y2);
    dE=sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));
    dM=fabs(x1-x2)+fabs(y1-y2);
    printf("%.6f",fabs(dM-dE));
    return 0;
}