/*
  author: honglan0301
  Sexy_goodier _ xiaoqing
 */
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cstdio>
#include <cctype>
#include <queue>
#include <map>
#include <unordered_map>
#include <cstdlib>
#include <ctime>
#include <vector>
#include <cmath>
#include <set>
#include <bitset>
#include <assert.h>
using namespace std;

//namespace Fread{const int SIZE=1<<20;char buf[SIZE],*S,*T;inline char getchar(){if(S==T){T=(S=buf)+fread(buf,1,SIZE,stdin);if(S==T)return'\n';}return*S++;}}using namespace Fread;namespace Fwrite{const int SIZE=1<<20;char buf[SIZE],*S=buf,*T=buf+SIZE;inline void flush(){fwrite(buf,1,S-buf,stdout);S=buf;}inline void putchar(char c){*S++=c;if(S==T)flush();}struct NTR{~NTR(){flush();}}ztr;}using namespace Fwrite;
//#define getchar Fread::getchar
//#define putchar Fwrite::putchar

namespace Fastio{struct Reader{template<typename T>Reader&operator>>(T&x){x=0;short f=1;char c=getchar();while(c<'0'||c>'9'){if(c=='-')f*=-1;c=getchar();}while(c>='0'&&c<='9')x=(x<<3)+(x<<1)+(c^48),c=getchar();x*=f;return*this;}Reader&operator>>(double&x){x=0;double t=0;short f=1,s=0;char c=getchar();while((c<'0'||c>'9')&&c!='.'){if(c=='-')f*=-1;c=getchar();}while(c>='0'&&c<='9'&&c!='.')x=x*10+(c^48),c=getchar();if(c=='.')c=getchar();else{x*=f;return*this;}while(c>='0'&&c<='9')t=t*10+(c^48),s++,c=getchar();while(s--)t/=10.0;x=(x+t)*f;return*this;}Reader&operator>>(long double&x){x=0;long double t=0;short f=1,s=0;char c=getchar();while((c<'0'||c>'9')&&c!='.'){if(c=='-')f*=-1;c=getchar();}while(c>='0'&&c<='9'&&c!='.')x=x*10+(c^48),c=getchar();if(c=='.')c=getchar();else{x*=f;return*this;}while(c>='0'&&c<='9')t=t*10+(c^48),s++,c=getchar();while(s--)t/=10.0;x=(x+t)*f;return*this;}Reader&operator>>(__float128&x){x=0;__float128 t=0;short f=1,s=0;char c=getchar();while((c<'0'||c>'9')&&c!='.'){if(c=='-')f*=-1;c=getchar();}while(c>='0'&&c<='9'&&c!='.')x=x*10+(c^48),c=getchar();if(c=='.')c=getchar();else{x*=f;return*this;}while(c>='0'&&c<='9')t=t*10+(c^48),s++,c=getchar();while(s--)t/=10.0;x=(x+t)*f;return*this;}Reader&operator>>(char&c){c=getchar();while(c==' '||c=='\n'||c=='\r')c=getchar();return*this;}Reader&operator>>(char*str){int len=0;char c=getchar();while(c==' '||c=='\n'||c=='\r')c=getchar();while(c!=' '&&c!='\n'&&c!='\r')str[len++]=c,c=getchar();str[len]='\0';return*this;}Reader&operator>>(string&str){str.clear();char c=getchar();while(c==' '||c=='\n'||c=='\r')c=getchar();while(c!=' '&&c!='\n'&&c!='\r')str.push_back(c),c=getchar();return*this;}Reader(){}}cin;const char endl='\n';struct Writer{const int Setprecision=6;typedef int mxdouble;template<typename T>Writer&operator<<(T x){if(x==0){putchar('0');return*this;}if(x<0)putchar('-'),x=-x;static short sta[40];short top=0;while(x>0)sta[++top]=x%10,x/=10;while(top>0)putchar(sta[top]+'0'),top--;return*this;}Writer&operator<<(double x){if(x<0)putchar('-'),x=-x;mxdouble _=x;x-=(double)_;static short sta[40];short top=0;while(_>0)sta[++top]=_%10,_/=10;if(top==0)putchar('0');while(top>0)putchar(sta[top]+'0'),top--;putchar('.');for(int i=0;i<Setprecision;i++)x*=10;_=x;while(_>0)sta[++top]=_%10,_/=10;for(int i=0;i<Setprecision-top;i++)putchar('0');while(top>0)putchar(sta[top]+'0'),top--;return*this;}Writer&operator<<(long double x){if(x<0)putchar('-'),x=-x;mxdouble _=x;x-=(long double)_;static short sta[40];short top=0;while(_>0)sta[++top]=_%10,_/=10;if(top==0)putchar('0');while(top>0)putchar(sta[top]+'0'),top--;putchar('.');for(int i=0;i<Setprecision;i++)x*=10;_=x;while(_>0)sta[++top]=_%10,_/=10;for(int i=0;i<Setprecision-top;i++)putchar('0');while(top>0)putchar(sta[top]+'0'),top--;return*this;}Writer&operator<<(__float128 x){if(x<0)putchar('-'),x=-x;mxdouble _=x;x-=(__float128)_;static short sta[40];short top=0;while(_>0)sta[++top]=_%10,_/=10;if(top==0)putchar('0');while(top>0)putchar(sta[top]+'0'),top--;putchar('.');for(int i=0;i<Setprecision;i++)x*=10;_=x;while(_>0)sta[++top]=_%10,_/=10;for(int i=0;i<Setprecision-top;i++)putchar('0');while(top>0)putchar(sta[top]+'0'),top--;return*this;}Writer&operator<<(char c){putchar(c);return*this;}Writer&operator<<(char*str){int cur=0;while(str[cur])putchar(str[cur++]);return*this;}Writer&operator<<(const char*str){int cur=0;while(str[cur])putchar(str[cur++]);return*this;}Writer&operator<<(string str){int st=0,ed=str.size();while(st<ed)putchar(str[st++]);return*this;}Writer(){}}cout;}using namespace Fastio;
#define cin Fastio::cin
#define cout Fastio::cout
#define endl Fastio::endl//;fflush(stdout)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define int long long
#define mod 998244353
#define eps 1e-6

int T,n,w[105][105];
double x[105],ns,ans;

double getrd(double l,double r)
{
	return l+(double)(rand())/(RAND_MAX)*(r-l);
}
int rd(int l,int r)
{
	return l+(rand())%(r-l+1);
}
double calc()
{
	double na=0;
	for(int i=1;i<=n;i++) for(int j=i+1;j<=n;j++) na+=x[i]*x[j]*w[i][j];
	return na;
}
double calf(int xx)
{
	double na=0; for(int i=1;i<=n;i++) if(i!=xx) na+=x[i]*x[xx]*w[i][xx]; return na;
}
double calf(int xx,int yy)
{
	double na=calf(xx)+calf(yy); na-=x[xx]*x[yy]*w[xx][yy]; return na;
}

double SA()
{
	double na=calc();
	for(double nt=1;nt>eps;nt*=0.9992)
	{
		int nx=rd(1,n),ny=rd(1,n); if(nx==ny) continue;
		double ns=x[nx]+x[ny];
		double nd=getrd(0,nt); double lx=x[nx],ly=x[ny];
		double delt=-calf(nx,ny);
		double nj=x[nx]*nd; x[nx]-=nj; x[ny]+=nj;  //cout<<nx<<" "<<ny<<" "<<ns<<" "<<nd<<" "<<x[nx]<<" "<<x[ny]<<endl;
		delt+=calf(nx,ny);
		//cout<<na<<" "<<x[1]<<" "<<x[2]<<" "<<x[3]<<" "<<delt<<endl;
		if(delt>0) na+=delt;
		else x[nx]=lx,x[ny]=ly;
	}
	return na;
}

signed main()
{
	//freopen("ex_C2.in","r",stdin);
	srand(time(0));
	cin>>T;
	while(T--)
	{
		cin>>n; for(int i=1;i<=n;i++) for(int j=1;j<=n;j++) cin>>w[i][j]; ans=0;
		for(int i=1;i<=25;i++)
		{
			ns=1; for(int j=1;j<=n-1;j++) x[j]=getrd(0,ns*2/(n-j+1)),ns-=x[j]; x[n]=ns;
			//cout<<x[1]<<" "<<x[2]<<" "<<x[3]<<endl;
			ans=max(ans,SA());
		}
		printf("%.9lf\n",ans);
	}
}