题解 | 绕距

#include<iostream>
#include<iomanip>
#include<cmath>
using namespace std;
int main(){
    int x1,y1,x2,y2;
    cin >> x1 >> y1 >> x2 >> y2;
    double de=sqrt(pow(x1-x2,2)+pow(y1-y2,2));
    int dm=abs(x1-x2)+abs(y1-y2);
    double result=fabs(dm-de);
    cout << fixed << setprecision(6) << result << endl;
    return 0;
}