Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)
	nodes := make([]Node, n)

	for i := 0; i < n; i++ {
		nodes[i].list = make([]int, 0)
		nodes[i].d = -1
	}

	for i := 0; i < n; i++ {
		u := getNextInt(scanner)
		k := getNextInt(scanner)
		u--
		for ii := 0; ii < k; ii++ {
			v := getNextInt(scanner)
			v--
			nodes[u].list = append(nodes[u].list, v)
		}
	}

	queue := make([]int, n)
	queue[0] = 0
	nodes[0].d = 0
	d := 0
	i, j := 0, 1
	for i < j {
		d++
		prev := j
		for i < prev {
			for k, l := 0, len(nodes[queue[i]].list); k < l && i < n; k++ {
				if nodes[nodes[queue[i]].list[k]].d != -1 {
					continue
				}
				nodes[nodes[queue[i]].list[k]].d = d
				queue[j] = nodes[queue[i]].list[k]
				j++
			}
			i++
		}
	}

	for i := 0; i < n; i++ {
		fmt.Fprintln(writer, fmt.Sprintf("%d %d", i+1, nodes[i].d))
	}

	writer.Flush()
}

// Node ...
type Node struct {
	list []int
	d    int
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<numeric>
#include<string>
#include<cmath>
#include<set>
#include<queue>
using namespace std;


vector<int> bfs(vector<vector<int> > &graph,int start){
	queue<int> todo;
	vector<int> dist(graph.size(),-1);
	dist[start] = 0;
	todo.push(start);
	while(!todo.empty()){
		int now = todo.front();
		todo.pop();
		for (int i=0;i<graph[now].size();i++){
			int nxt = graph[now][i];
			if (dist[nxt] != -1) continue;
			dist[nxt] = dist[now] + 1;
			todo.push(nxt);
		}
	}
	return dist;
}



int main(){
	int n; cin >> n;
	vector<vector<int> > graph(n+1);
	for (int i = 0; i < n; i++){
		int v, k; cin >> v >> k;
		for (int j = 0; j < k; j++) {
			int in; cin >> in;
			graph[v].push_back(in);
		}
	}
	vector<int> dist;
	dist = bfs(graph,1);


	for (int i=1;i<n+1;i++){
		cout << i << " " << dist[i] << endl;
	}

	return 0;
}

C++: #include <bits/stdc++.h>
#include <math.h>

using namespace std;

long long inf=1000000007;

int main(){
	long long n;
	cin>>n;
	vector<vector<long long>> kankei(n+1);
	vector<long long> dis(n+1,-1);

	for(long long i=0;i<n;i++){
		long long u,k;
		cin>>u>>k;
		for(long long j=0;j<k;j++){
			long long hoge;
			cin>>hoge;
			kankei.at(u).push_back(hoge);
		}
	}

	queue<long long> que;
	que.push(1);
	dis.at(1)=0;

	while(!que.empty()){
		long long now=que.front();
		que.pop();

		for(auto a:kankei.at(now)){
			if(dis.at(a)!=-1) continue;
			que.push(a);
			dis.at(a)=dis.at(now)+1;
		}
	}

	for(long long i=1;i<=n;i++){
		cout<<i<<" "<<dis.at(i)<<endl;
	}

	return 0;
}

C++: #include<iostream>
#include<vector>
using namespace std;

int BFS(int s, int t, const vector<vector<int> >& G){
    vector<int> stock1;
    vector<int> stock2;
    stock1.push_back(s);
    int d = 0;
    while (1) {
        for (int i = 0; i < stock1.size(); i++) {
            if (stock1[i] == t) return d;
            for (int j = 0; j < G[stock1[i]].size(); j++) {
                stock2.push_back(G[stock1[i]][j]);
            }
        }
        if (stock2.empty()) return -1;
        stock1.clear();
        stock1.swap(stock2);
        d++;
    }
}

int main(){
    int n;
    cin >> n;
    vector<vector<int> > G(n + 1);
    for (int i = 0; i < n; i++) {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; j++) {
            int v;
            cin >> v;
            G[u].push_back(v);
        }
    }
    for (int i = 1; i <= n; i++) {
        cout << i << " " << BFS(1, i, G) << endl;
    }
    return 0;
}

C++: #include <bits/stdc++.h>
#define _GLIBCXX_DEBUG
#define rep(i,n) for (int i = 0; i < (n); ++i)
using namespace std;
using ll = long long;
using P = pair<int,int>;

using Graph = vector<vector<int>>;

int main(){
int n;
cin >> n;
Graph G(n+1);
rep(i,n)
{
  int v;
  cin>>v;
  int k;
  cin >> k;
  rep(j,k)
  {int vt;
   cin >>vt;
   G[v].push_back(vt); 
  }
}

vector<int> dist(n+1,-1);
queue<int> que;

dist[1]=0;
que.push(1);

while (!que.empty())
{
  int v = que.front();
  que.pop();
  //cout << G[1].size()<<endl;
  rep(i,G[v].size())
  { int newv =G[v][i];
   if(dist[newv]==-1)
    {que.push(newv);
     dist[newv]=dist[v]+1;}
  }

}

rep(i,n)
{
  cout<< i+1 <<" "<<dist[i+1]<<endl;

}

return 0;
}
//

C++: #include <iostream>
#include <queue>
using namespace std;

#define N 100
#define INFTY (1 << 21)

int n, M[N][N];
int d[N];

void bfs(int s) {
  queue<int> q;
  q.push(s);
  for ( int i = 0; i < n; i++ ) {
    d[i] = INFTY;
  }
  d[s] = 0;
  int u;
  while ( !q.empty() ) {
    u = q.front(); q.pop();
    for ( int v = 0; v < n; v++ ) {
      if ( M[u][v] == 0 ) continue;
      if ( d[v] != INFTY ) continue;
      d[v] = d[u] + 1;
      q.push(v);
    }
  }
  for ( int i = 0; i < n; i++ ) {
    cout << i + 1 << " " << ( (d[i] == INFTY) ? (-1) : d[i] ) << endl;
  }
}

C++: #include<cstdio>
#include<queue>
using namespace std;
static const int INF=(1<<21);
static const int MAXN=101;
struct p{
	int d;
	int cnt;
};
int main()
{
	int n,m[MAXN][MAXN],i,j,u,k,v,l,o,c=1,t[MAXN];
	p e,f;
	queue<p> q;
	bool used[MAXN]={};
	scanf("%d",&n);
	for(i=1;i<n+1;i++){
		for(j=1;j<n+1;j++){
			m[i][j]=INF;
		}
	}
	for(i=0;i<n;i++){
		scanf("%d %d",&u,&k);
		for(j=0;j<k;j++){
			scanf("%d",&v);
			m[u][v]=1;
		}
	}
	used[1]=true;
	e.d=1;
	e.cnt=0;
	q.push(e);
	while(!q.empty()){
		e=q.front();
		q.pop();
		o=0;
		for(i=1;i<n+1;i++){
			if(m[e.d][i]==1&&used[i]==false){
				f.d=i;
				f.cnt=e.cnt+1;
				q.push(f);
				used[i]=true;
				t[i]=e.cnt+1;
				o=1;
			}
		}
		if(o==1){
			c++;
		}
	}
	for(i=1;i<n+1;i++){
		if(used[i]==true){
			printf("%d %d\n",i,t[i]);
		}
		else{
			printf("%d -1\n",i);
		}
	}
	return 0;
}

C++: #include<iostream>
#include<queue>

using namespace std;
static const int N = 100;
static const int INFTY = (1<<21);

int n, M[N][N];
int d[N];

void bfs(int s) {
    queue<int> q;
    q.push(s);
    for (int i = 0; i < n; i++) {
        d[i] = INFTY;
    }
    d[s] = 0;
    int u;
    while( !q.empty()) {
        u = q.front();
        q.pop();
        for (int v = 0; v < n; v++) {
            if (M[u][v] == 0) continue;
            if (d[v] != INFTY) continue;
            d[v] = d[u] + 1;
            q.push(v);
        }
    }
    for (int i = 0; i < n; i++) {
        cout << i + 1 << " " << ( (d[i] == INFTY) ? (-1) : d[i]) << endl;
    }
}

int main() {
    int u, k, v;
    
    cin >> n;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) M[i][j] = 0;
    }
    
    for (int i = 0; i < n; i++) {
        cin >> u >> k;
        u--;
        for (int j = 0; j < k; j++) {
            cin >> v;
            v--;
            M[u][v] = 1;
        }
    }
    
    bfs(0);
    
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

typedef long long ll;


int d[200];
bool table[200][200];

void init(){
    for(int i=0;i<200;i++){
        d[i]=-1;
        for(int j=0;j<200;j++){
            table[i][j]=false;
        }
    }
}

void bfs(int itr, int dis, int n){
    d[itr] = dis;
    for(int i=0;i<n;i++){
        if(table[itr][i]&&(d[i]<0||d[i]>dis+1)){
            bfs(i, dis+1,n);
        }
    }
}

void solve(int n){
    bfs(0,0,n);
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);

    init();
    int n;
    cin >> n;
    int u,k,v;
    for(int i=0;i<n;i++){
        cin >> u >> k;
        for(int j=0;j<k;j++){
            cin >> v;
            table[u-1][v-1]=true;
        }
    }

    solve(n);

    for(int i=0;i<n;i++){
        cout << i+1 << " " << d[i] << endl;
    }

    return 0;
}