题解 | 绕距

import java.util.*;
public class Main{
    public static void main(String[] args){
        double x1,x2,y1,y2,de,dm;
        Scanner scan = new Scanner(System.in);
        x1 = scan.nextDouble();
        y1 = scan.nextDouble();
        x2 = scan.nextDouble();
        y2 = scan.nextDouble();
        de = Math.pow(Math.pow((x1-x2),2)+Math.pow((y1-y2),2),0.5);
        dm = Math.abs(x1-x2)+Math.abs(y1-y2);
        System.out.printf("%.18f",Math.abs(dm-de));
    }
}