Go: package main

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

func main() {
	scn := bufio.NewScanner(os.Stdin)
	scn.Split(bufio.ScanWords)
	nextInt := func() int { scn.Scan(); r, _ := strconv.Atoi(scn.Text()); return r }
	w := bufio.NewWriter(os.Stdout)

	n := nextInt()
	vecs := make([][]int, n)
	for i := 0; i < n; i++ {
		u := nextInt()
		k := nextInt()
		for j := 0; j < k; j++ {
			vecs[u-1] = append(vecs[u-1], nextInt()-1)
		}
	}

	ds := make([]int, 0, n)
	for i := 0; i < n; i++ {
		ds = append(ds, -1)
	}

	q := make([]int, 0, n)
	q = append(q, 0)
	ds[0] = 0

	for len(q) > 0 {
		i := pop(&q)
		for _, v := range vecs[i] {
			if ds[v] == -1 {
				ds[v] = ds[i]+1
				q = append(q, v)
			}
		}
	}

	for i, d := range ds {
		fmt.Fprintln(w, i+1, d)
	}

	w.Flush()
}

func pop(q *[]int) int {
	v := (*q)[0]
	*q = (*q)[1:]
	return v
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;


vector<int>v[105];
int t[105]={};
bool flag[105]={};
void BFS(int p)
{
	queue<int>Q;	
	Q.push(p);
	flag[p]=true;
	while(!Q.empty())
	{
		p=Q.front();
		Q.pop();
		for(int i=0;i<v[p].size();i++)
		{
			if(!flag[v[p][i]])
			{
				t[v[p][i]]=t[p]+1;
				Q.push(v[p][i]);
			}
			flag[v[p][i]]=true;
		}
	}
}
int main()
{	
	int n,a,b,k;
	cin>>n;
	for(int i=0;i<n;i++)
	{
		cin>>a>>k;
		for(int j=0;j<k;j++)
		{
			cin>>b;
			v[a].push_back(b);
		}
	}
	BFS(1);
	for(int i=1;i<=n;i++)
	{
		cout<<i<<" ";
		if(i!=1&&t[i]==0)cout<<-1<<endl;
		else cout<<t[i]<<endl;
	}
	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;
            //cout <<v<<" "<<d[v];
            d[v] = d[u] + 1;
            //cout <<"->"<< d[v] << endl;
            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;
#define _GLIBCXX_DEBUG

int main() {
  int n;
  cin >> n;
  vector<vector<int>> dst(n + 1);
  for (int i = 1; i <= n; i++) {
    int u, k;
    cin >> u >> k;
    for (int j = 0; j < k; j++) {
      int v;
      cin >> v;
      dst[i].push_back(v);
    }
  }
  queue<int> Q;
  vector<int> ans(n + 1, -1);
  ans[1] = 0;
  Q.push(1);
  while (Q.size()) {
    int p = Q.front();
    for (int d : dst[p]) {
      if (ans[d] == -1) {
        ans[d] = ans[p] + 1;
        Q.push(d);
      }
    }
    Q.pop();
  }
  for (int i = 1; i <= n; i++) {
    cout << i << ' ' << ans[i] << endl;
  }
}

C++: #include <algorithm>
#include <iostream>
#include <queue>
#include <vector>
using namespace std;
using Graph=vector<vector<int>>;
typedef long long ll;
int dx[]={0,1,0,-1};
int dy[]={1,0,-1,0};

int main(){
    int n;cin>>n;
    Graph G(n+2);
    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);
        }
    }
    bool ans_check=false;
    vector<int> b(n+2,1000000);
    queue<int> q;
    b[1]=0;
    q.push(1);
    while(!q.empty()){
        int x=q.front();q.pop();
        for(int A=0;A<G[x].size();A++){
            int check_x=G[x][A];
            if(b[check_x]==1000000){
                q.push(check_x);
                b[check_x]=b[x]+1;
            }
        }
    }
    for(int i=1;i<n+1;i++){
        if(b[i]==1000000) b[i]=-1;
        cout<<i<<' '<<b[i]<<endl;
    }
}

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;
    }
  }

  dfs(0);

  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define REP(i,n) for(int i=0; i<(n); i++)
#define REP2(i,x,n) for(int i=x; i<(n); i++)
#define PRINT(x) cout<<(x)<<endl
#define INF 1000000000000 // 10^12
#define MOD 1000000007 // 10^9+7
#define PB push_back
#define MP make_pair

const int MAX_N = 100;

int n, u, k, v;

vector<int> G[MAX_N];
int d[MAX_N]; // distance from 0

int main() {
    // input
    cin >> n;
    REP(i, n) {
        cin >> u >> k;
        REP(j, k) {
            cin >> v;
            G[u-1].PB(v-1);
        }
    }

    // init d
    REP(i, n) d[i] = -1;

    // BFS
    queue<int> Q;
    Q.push(0);
    d[0] = 0;
    while (Q.size()) {
        int pos = Q.front(); Q.pop();
        REP(i, G[pos].size()) {
            int to = G[pos][i];
            if (d[to] != -1) continue;
            Q.push(to);
            d[to] = d[pos] + 1;
        }
    }

    // output
    REP(i, n) {
        int id = i + 1;
        printf("%d %d\n", id, d[i]);
    }

    return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep1(i, n) for (int i = 1; i < (n); ++i)
using namespace std;
typedef long long ll;

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

    int n;
    cin >> n;

    vector<vector<int>> g(n);
    rep(i, n){
        int u, k;
        cin >> u >> k;
        --u;

        rep(j, k){
            int v;
            cin >> v;
            --v;

            g[u].push_back(v);
        }
    }

    queue<int> q;
    vector<int> dist(n, -1);
    q.push(0);
    dist[0] = 0;
    while(!q.empty()){
        int v = q.front();
        q.pop();
        
        for(int nv : g[v]){
            if(dist[nv] != -1) continue;

            dist[nv] = dist[v] + 1;
            q.push(nv);
        }
    }

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

    return 0;
}