题解 | 绕距

#include <iostream>
#include<cmath>
#include <iomanip>
using namespace std;

int main() {
    int x1, x2,x3,x4;
    cin>>x1>>x2>>x3>>x4;
    double DE=sqrt((x1-x3)*(x1-x3)+(x2-x4)*(x2-x4));
    double DM=fabs(x1-x3)+fabs(x2-x4);
    double R=fabs(DM-DE);
     cout << fixed << setprecision(18) << R << endl;
    return 0;
    
}
// 64 位输出请用 printf("%lld")