题解

#include <iostream>
using namespace std;
const int N =100001;
typedef double dd;//要小数才能返回
int n;
dd x[N],y[N];
dd calc_dis(dd x1,dd y1,dd x2,dd y2)
{
	return sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));
}
int main(){
	cin>>n;
	for(int i=1;i<=n;i++)cin>>x[i]>>y[i];//枚举 
	for(int i=1;i<=n;i++){//枚举3个点 
		for(int j=1;j<=n;j++){
			cout<<fixed<<setprecision(2)<<calc_dis(x[i],y[i],x[j],y[j])<<" ";
		}
		cout<<"\n";
	}
	return 0;	
}