1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
#include<bits/stdc++.h>

using namespace std;

struct ala{
	int l;
	int k;
	int war;
};
bool comp(ala a,ala b)
{
	return a.war<b.war;
}

void solve()
{
	int a;
	cin>>a;
	
	vector<vector<int>>v(a+1);
	int odl[a+1][a+1];
	vector<pair<int,int>>par;
	for(int z=1;z<=a;z++)
	{
		string s;
		cin>>s;
		for(int w=1;w<=a;w++)
		{
			odl[z][w]=0;
			if(w>z)par.push_back({z,w});
			if(s[w-1]=='1')
			{
				v[z].push_back(w);
				v[w].push_back(z);
			}
		}
	}
	vector<ala>war;
	for(int z=1;z<=a;z++)
	{
		vector<int>czy(a+1,0);
		queue<ala>q;
		q.push({z,z,0});
		while(!q.empty())
		{
			ala pom=q.front();
			q.pop();
			if(czy[pom.k])continue;
			czy[pom.k]=1;
			odl[z][pom.k]=pom.war;
			if(pom.k>z)war.push_back({z,pom.k,pom.war});
			for(auto w:v[pom.k])q.push({w,w,pom.war+1});
		}
	}
	sort(war.begin(),war.end(),comp);
	int wyn=war.back().war;
	
	random_shuffle(par.begin(),par.end());
	
	for(auto z:par)
	{
		int akt=-1;
		
		int ta=z.first;
		int tb=z.second;
		
		for(int w=war.size()-1;w>=0;w--)
		{
			auto pom=war[w];
			int rel=pom.war;
			if(rel<=akt)break;
			int l=pom.l;
			int k=pom.k;
			
			rel=min(rel,odl[l][ta]+odl[tb][k]);
			rel=min(rel,odl[l][tb]+odl[ta][k]);
			
			if(akt==-1)akt=rel;
			else
			{
				akt=max(akt,rel);
			}
			if(akt>=wyn)break;
		}
		wyn=min(wyn,akt);
		if(wyn==1)break;
	}
	
	cout<<wyn<<"\n";
}


int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	
	int h=1;
	cin>>h;
	while(h--)solve();
	
	return 0;
}