题解 | 绕距

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

int main() 
{
    float x1,x2,y1,y2,de,dm,rj;
    cin>>x1;cin>>y1;
    cin>>x2;cin>>y2;
    de=sqrt(pow(x1-x2,2)+pow(y1-y2,2));//pow(a,b),引用cmath的幂函数，b为次方
    dm=abs(x1-x2)+abs(y1-y2);//abs()为绝对值函数，引用自cmath
    rj=abs(dm-de);
    cout<<setiosflags(ios::fixed)<<setprecision(10)<<rj;
    return 0;
}